test: alert manager supported notifier test

ee/query-service/rules/anomaly.go

@@ -277,8 +277,23 @@ func (r *AnomalyRule) Eval(ctx context.Context, ts time.Time) (int, error) {
 
 		annotations := make(ruletypes.Labels, 0, len(r.Annotations().Map()))
 		for name, value := range r.Annotations().Map() {
+			// no need to expand custom templating annotations — they get expanded in the notifier layer
+			if ruletypes.IsCustomTemplatingAnnotation(name) {
+				annotations = append(annotations, ruletypes.Label{Name: name, Value: value})
+				continue
+			}
 			annotations = append(annotations, ruletypes.Label{Name: name, Value: expand(value)})
 		}
+		// Add values to be used in notifier layer for notification templates
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationValue, Value: value})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationThresholdValue, Value: threshold})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationCompareOp, Value: smpl.CompareOperator.Literal()})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationMatchType, Value: smpl.MatchType.Literal()})
+
+		if smpl.IsRecovering {
+			lb.Set(ruletypes.LabelIsRecovering, "true")
+		}
+
 		if smpl.IsMissing {
 			lb.Set(ruletypes.AlertNameLabel, "[No data] "+r.Name())
 			lb.Set(ruletypes.NoDataLabel, "true")

pkg/alertmanager/alertmanagernotify/email/email.go

@@ -32,7 +32,12 @@ import (
 	"sync"
 	"time"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/emailtypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	commoncfg "github.com/prometheus/common/config"
 
 	"github.com/prometheus/alertmanager/config"
@@ -47,16 +52,17 @@ const (
 
 // Email implements a Notifier for email notifications.
 type Email struct {
-	conf     *config.EmailConfig
-	tmpl     *template.Template
-	logger   *slog.Logger
-	hostname string
+	conf      *config.EmailConfig
+	tmpl      *template.Template
+	logger    *slog.Logger
+	hostname  string
+	processor alertmanagertypes.NotificationProcessor
 }
 
 var errNoAuthUsernameConfigured = errors.NewInternalf(errors.CodeInternal, "no auth username configured")
 
 // New returns a new Email notifier.
-func New(c *config.EmailConfig, t *template.Template, l *slog.Logger) *Email {
+func New(c *config.EmailConfig, t *template.Template, l *slog.Logger, proc alertmanagertypes.NotificationProcessor) *Email {
 	if _, ok := c.Headers["Subject"]; !ok {
 		c.Headers["Subject"] = config.DefaultEmailSubject
 	}
@@ -72,7 +78,7 @@ func New(c *config.EmailConfig, t *template.Template, l *slog.Logger) *Email {
 	if err != nil {
 		h = "localhost.localdomain"
 	}
-	return &Email{conf: c, tmpl: t, logger: l, hostname: h}
+	return &Email{conf: c, tmpl: t, logger: l, hostname: h, processor: proc}
 }
 
 // auth resolves a string of authentication mechanisms.
@@ -254,6 +260,16 @@ func (n *Email) Notify(ctx context.Context, as ...*types.Alert) (bool, error) {
 		}
 	}
 
+	// Prepare the content for the email
+	title, htmlBody, err := n.prepareContent(ctx, as, data)
+	if err != nil {
+		n.logger.ErrorContext(ctx, "failed to prepare notification content", errors.Attr(err))
+		return false, err
+	}
+	if title != "" {
+		n.conf.Headers["Subject"] = title
+	}
+
 	// Send the email headers and body.
 	message, err := c.Data()
 	if err != nil {
@@ -345,7 +361,7 @@ func (n *Email) Notify(ctx context.Context, as ...*types.Alert) (bool, error) {
 		}
 	}
 
-	if len(n.conf.HTML) > 0 {
+	if htmlBody != "" {
 		// Html template
 		// Preferred alternative placed last per section 5.1.4 of RFC 2046
 		// https://www.ietf.org/rfc/rfc2046.txt
@@ -356,12 +372,8 @@ func (n *Email) Notify(ctx context.Context, as ...*types.Alert) (bool, error) {
 		if err != nil {
 			return false, errors.WrapInternalf(err, errors.CodeInternal, "create part for html template")
 		}
-		body, err := n.tmpl.ExecuteHTMLString(n.conf.HTML, data)
-		if err != nil {
-			return false, errors.WrapInternalf(err, errors.CodeInternal, "execute html template")
-		}
 		qw := quotedprintable.NewWriter(w)
-		_, err = qw.Write([]byte(body))
+		_, err = qw.Write([]byte(htmlBody))
 		if err != nil {
 			return true, errors.WrapInternalf(err, errors.CodeInternal, "write HTML part")
 		}
@@ -390,6 +402,90 @@ func (n *Email) Notify(ctx context.Context, as ...*types.Alert) (bool, error) {
 	return false, nil
 }
 
+// prepareContent extracts custom templates from alerts, runs the notification processor,
+// and returns the resolved subject title (if any) and the HTML body for the email.
+func (n *Email) prepareContent(ctx context.Context, alerts []*types.Alert, data *template.Data) (string, string, error) {
+	// run the notification processor to get the title and body
+	customTitle, customBody := alertmanagertemplate.ExtractTemplatesFromAnnotations(alerts)
+	result, err := n.processor.ProcessAlertNotification(ctx, alertmanagertypes.NotificationProcessorInput{
+		TitleTemplate:        customTitle,
+		BodyTemplate:         customBody,
+		DefaultTitleTemplate: n.conf.Headers["Subject"],
+		// no templating needed for email body as it will be handled with legacy templating
+		DefaultBodyTemplate: alertmanagertypes.NoOpTemplateString,
+	}, alerts, markdownrenderer.MarkdownFormatHTML)
+	if err != nil {
+		return "", "", err
+	}
+
+	title := result.Title
+
+	// If custom templated, render via the HTML layout template
+	if result.IsCustomTemplated() {
+		// Add buttons to each of the bodies if the related logs and traces links are present in annotations
+		for i := range result.Body {
+			relatedLogsLink := alerts[i].Annotations[ruletypes.AnnotationRelatedLogs]
+			relatedTracesLink := alerts[i].Annotations[ruletypes.AnnotationRelatedTraces]
+			if relatedLogsLink != "" {
+				result.Body[i] += htmlButton("View Related Logs", string(relatedLogsLink))
+			}
+			if relatedTracesLink != "" {
+				result.Body[i] += htmlButton("View Related Traces", string(relatedTracesLink))
+			}
+		}
+
+		htmlContent, renderErr := n.processor.RenderEmailNotification(ctx, emailtypes.TemplateNameAlertEmailNotification, result, alerts)
+		if renderErr == nil {
+			return title, htmlContent, nil
+		}
+		n.logger.WarnContext(ctx, "custom email template rendering failed, falling back to default", errors.Attr(renderErr))
+	}
+
+	// Default templated body: use the HTML config template if available
+	if len(n.conf.HTML) > 0 {
+		body, err := n.tmpl.ExecuteHTMLString(n.conf.HTML, data)
+		if err != nil {
+			return "", "", errors.WrapInternalf(err, errors.CodeInternal, "execute html template")
+		}
+		return title, body, nil
+	}
+
+	// No HTML template configured, fallback to plain HTML templating
+	if result.IsCustomTemplated() {
+		var b strings.Builder
+		for _, part := range result.Body {
+			b.WriteString("<div>")
+			b.WriteString(part)
+			b.WriteString("</div>")
+		}
+		return title, b.String(), nil
+	}
+	return title, "", nil
+}
+
+func htmlButton(text, url string) string {
+	return fmt.Sprintf(`
+	<a href="%s" target="_blank" style="text-decoration: none;">
+<button style="
+    padding: 6px 16px;
+    /* Default System Font */
+    font-family: sans-serif;
+    font-size: 14px;
+    font-weight: 500;
+    line-height: 1.5;
+    /* Light Theme & Dynamic Background (Solid) */
+    color: #111827;
+    background-color: #f9fafb;
+    /* Static Outline */
+    border: 1px solid #d1d5db;
+    border-radius: 4px;
+    cursor: pointer;
+">
+  %s
+</button>
+</a>`, url, text)
+}
+
 type loginAuth struct {
 	username, password string
 }

pkg/alertmanager/alertmanagernotify/email/email_test.go

@@ -32,6 +32,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"log/slog"
 	"net"
 	"net/http"
 	"net/url"
@@ -41,7 +42,13 @@ import (
 	"testing"
 	"time"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertnotificationprocessor"
+	"github.com/SigNoz/signoz/pkg/emailing/templatestore/filetemplatestore"
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	"github.com/emersion/go-smtp"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
@@ -58,6 +65,13 @@ import (
 	"github.com/prometheus/alertmanager/types"
 )
 
+func newTestProcessor(tmpl *template.Template) alertmanagertypes.NotificationProcessor {
+	logger := slog.Default()
+	templater := alertmanagertemplate.New(tmpl, logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(logger)
+	return alertnotificationprocessor.New(templater, renderer, filetemplatestore.NewEmptyStore(), logger)
+}
+
 const (
 	emailNoAuthConfigVar = "EMAIL_NO_AUTH_CONFIG"
 	emailAuthConfigVar   = "EMAIL_AUTH_CONFIG"
@@ -186,7 +200,7 @@ func notifyEmailWithContext(ctx context.Context, t *testing.T, cfg *config.Email
 		return nil, false, err
 	}
 
-	email := New(cfg, tmpl, promslog.NewNopLogger())
+	email := New(cfg, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
 
 	retry, err := email.Notify(ctx, firingAlert)
 	if err != nil {
@@ -730,7 +744,7 @@ func TestEmailRejected(t *testing.T) {
 	tmpl, firingAlert, err := prepare(cfg)
 	require.NoError(t, err)
 
-	e := New(cfg, tmpl, promslog.NewNopLogger())
+	e := New(cfg, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
 
 	// Send the alert to mock SMTP server.
 	retry, err := e.Notify(context.Background(), firingAlert)
@@ -1054,6 +1068,100 @@ func TestEmailImplicitTLS(t *testing.T) {
 	}
 }
 
+func TestPrepareContent(t *testing.T) {
+	t.Run("custom template", func(t *testing.T) {
+		tmpl, err := template.FromGlobs([]string{})
+		require.NoError(t, err)
+		tmpl.ExternalURL, _ = url.Parse("http://am")
+
+		bodyTpl := "line $labels.instance"
+		a1 := &types.Alert{
+			Alert: model.Alert{
+				Labels: model.LabelSet{
+					model.LabelName("instance"): model.LabelValue("one"),
+				},
+				Annotations: model.LabelSet{
+					model.LabelName(ruletypes.AnnotationBodyTemplate): model.LabelValue(bodyTpl),
+				},
+			},
+		}
+		a2 := &types.Alert{
+			Alert: model.Alert{
+				Labels: model.LabelSet{
+					model.LabelName("instance"): model.LabelValue("two"),
+				},
+				Annotations: model.LabelSet{
+					model.LabelName(ruletypes.AnnotationBodyTemplate): model.LabelValue(bodyTpl),
+				},
+			},
+		}
+		alerts := []*types.Alert{a1, a2}
+
+		cfg := &config.EmailConfig{Headers: map[string]string{"Subject": "subj"}}
+		n := New(cfg, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
+
+		ctx := context.Background()
+		data := notify.GetTemplateData(ctx, tmpl, alerts, n.logger)
+		_, htmlBody, err := n.prepareContent(ctx, alerts, data)
+		require.NoError(t, err)
+		// Goldmark will append newlines inside paragraph tags.
+		require.Equal(t, "<div><p>line one</p><p></p></div><div><p>line two</p><p></p></div>", htmlBody)
+	})
+
+	t.Run("default template with HTML and custom title template", func(t *testing.T) {
+		tmpl, err := template.FromGlobs([]string{})
+		require.NoError(t, err)
+		tmpl.ExternalURL, _ = url.Parse("http://am")
+
+		firingAlert := &types.Alert{
+			Alert: model.Alert{
+				Labels: model.LabelSet{},
+				Annotations: model.LabelSet{
+					model.LabelName(ruletypes.AnnotationTitleTemplate): model.LabelValue("fixed from $status"),
+				},
+				StartsAt: time.Now(),
+				EndsAt:   time.Now().Add(time.Hour),
+			},
+		}
+		alerts := []*types.Alert{firingAlert}
+		cfg := &config.EmailConfig{
+			Headers: map[string]string{},
+			HTML:    "Status: {{ .Status }}",
+		}
+		n := New(cfg, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
+
+		ctx := context.Background()
+		data := notify.GetTemplateData(ctx, tmpl, alerts, n.logger)
+		title, htmlBody, err := n.prepareContent(ctx, alerts, data)
+		require.NoError(t, err)
+		require.Equal(t, "Status: firing", htmlBody)
+		require.Equal(t, "fixed from firing", title)
+	})
+
+	t.Run("default template without HTML", func(t *testing.T) {
+		cfg := &config.EmailConfig{Headers: map[string]string{"Subject": "the email subject"}}
+		tmpl, err := template.FromGlobs([]string{})
+		require.NoError(t, err)
+		tmpl.ExternalURL, _ = url.Parse("http://am")
+		n := New(cfg, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
+
+		firingAlert := &types.Alert{
+			Alert: model.Alert{
+				Labels:   model.LabelSet{},
+				StartsAt: time.Now(),
+				EndsAt:   time.Now().Add(time.Hour),
+			},
+		}
+		alerts := []*types.Alert{firingAlert}
+		ctx := context.Background()
+		data := notify.GetTemplateData(ctx, tmpl, alerts, n.logger)
+		title, htmlBody, err := n.prepareContent(ctx, alerts, data)
+		require.NoError(t, err)
+		require.Equal(t, "", htmlBody)
+		require.Equal(t, "the email subject", title)
+	})
+}
+
 func ptrTo(b bool) *bool {
 	return &b
 }

pkg/alertmanager/alertmanagernotify/msteamsv2/msteamsv2.go

@@ -24,7 +24,10 @@ import (
 	"slices"
 	"strings"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -53,6 +56,7 @@ type Notifier struct {
 	retrier      *notify.Retrier
 	webhookURL   *config.SecretURL
 	postJSONFunc func(ctx context.Context, client *http.Client, url string, body io.Reader) (*http.Response, error)
+	processor    alertmanagertypes.NotificationProcessor
 }
 
 // https://learn.microsoft.com/en-us/connectors/teams/?tabs=text1#adaptivecarditemschema
@@ -103,7 +107,7 @@ type teamsMessage struct {
 }
 
 // New returns a new notifier that uses the Microsoft Teams Power Platform connector.
-func New(c *config.MSTeamsV2Config, t *template.Template, titleLink string, l *slog.Logger, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
+func New(c *config.MSTeamsV2Config, t *template.Template, titleLink string, l *slog.Logger, proc alertmanagertypes.NotificationProcessor, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
 	client, err := notify.NewClientWithTracing(*c.HTTPConfig, Integration, httpOpts...)
 	if err != nil {
 		return nil, err
@@ -118,6 +122,7 @@ func New(c *config.MSTeamsV2Config, t *template.Template, titleLink string, l *s
 		retrier:      &notify.Retrier{},
 		webhookURL:   c.WebhookURL,
 		postJSONFunc: notify.PostJSON,
+		processor:    proc,
 	}
 
 	return n, nil
@@ -137,25 +142,11 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 		return false, err
 	}
 
-	title := tmpl(n.conf.Title)
-	if err != nil {
-		return false, err
-	}
-
 	titleLink := tmpl(n.titleLink)
 	if err != nil {
 		return false, err
 	}
 
-	alerts := types.Alerts(as...)
-	color := colorGrey
-	switch alerts.Status() {
-	case model.AlertFiring:
-		color = colorRed
-	case model.AlertResolved:
-		color = colorGreen
-	}
-
 	var url string
 	if n.conf.WebhookURL != nil {
 		url = n.conf.WebhookURL.String()
@@ -167,6 +158,12 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 		url = strings.TrimSpace(string(content))
 	}
 
+	bodyBlocks, err := n.prepareContent(ctx, as)
+	if err != nil {
+		n.logger.ErrorContext(ctx, "failed to prepare notification content", errors.Attr(err))
+		return false, err
+	}
+
 	// A message as referenced in https://learn.microsoft.com/en-us/connectors/teams/?tabs=text1%2Cdotnet#request-body-schema
 	t := teamsMessage{
 		Type: "message",
@@ -178,17 +175,7 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 					Schema:  "http://adaptivecards.io/schemas/adaptive-card.json",
 					Type:    "AdaptiveCard",
 					Version: "1.2",
-					Body: []Body{
-						{
-							Type:   "TextBlock",
-							Text:   title,
-							Weight: "Bolder",
-							Size:   "Medium",
-							Wrap:   true,
-							Style:  "heading",
-							Color:  color,
-						},
-					},
+					Body:    bodyBlocks,
 					Actions: []Action{
 						{
 							Type:  "Action.OpenUrl",
@@ -204,20 +191,6 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 		},
 	}
 
-	// add labels and annotations to the body of all alerts
-	for _, alert := range as {
-		t.Attachments[0].Content.Body = append(t.Attachments[0].Content.Body, Body{
-			Type:   "TextBlock",
-			Text:   "Alerts",
-			Weight: "Bolder",
-			Size:   "Medium",
-			Wrap:   true,
-			Color:  color,
-		})
-
-		t.Attachments[0].Content.Body = append(t.Attachments[0].Content.Body, n.createLabelsAndAnnotationsBody(alert)...)
-	}
-
 	var payload bytes.Buffer
 	if err = json.NewEncoder(&payload).Encode(t); err != nil {
 		return false, err
@@ -237,6 +210,79 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 	return shouldRetry, err
 }
 
+// prepareContent prepares the body blocks for the templated title and body.
+func (n *Notifier) prepareContent(ctx context.Context, alerts []*types.Alert) ([]Body, error) {
+	// run the notification processor to get the title and body
+	customTitle, customBody := alertmanagertemplate.ExtractTemplatesFromAnnotations(alerts)
+	result, err := n.processor.ProcessAlertNotification(ctx, alertmanagertypes.NotificationProcessorInput{
+		TitleTemplate:        customTitle,
+		BodyTemplate:         customBody,
+		DefaultTitleTemplate: n.conf.Title,
+		// the default body template is not used and instead we add collection of labels and annotations for each alert
+		DefaultBodyTemplate: alertmanagertypes.NoOpTemplateString,
+	}, alerts, markdownrenderer.MarkdownFormatNoop)
+	if err != nil {
+		return nil, err
+	}
+
+	blocks := []Body{}
+
+	// common color for the title block
+	aggregateAlerts := types.Alerts(alerts...)
+	color := colorGrey
+	switch aggregateAlerts.Status() {
+	case model.AlertFiring:
+		color = colorRed
+	case model.AlertResolved:
+		color = colorGreen
+	}
+
+	// add title block
+	blocks = append(blocks, Body{
+		Type:   "TextBlock",
+		Text:   result.Title,
+		Weight: "Bolder",
+		Size:   "Medium",
+		Wrap:   true,
+		Style:  "heading",
+		Color:  color,
+	})
+
+	// handle default templated body
+	if result.IsDefaultTemplatedBody {
+		for _, alert := range alerts {
+			blocks = append(blocks, Body{
+				Type:   "TextBlock",
+				Text:   "Alerts",
+				Weight: "Bolder",
+				Size:   "Medium",
+				Wrap:   true,
+				Color:  color,
+			})
+			blocks = append(blocks, n.createLabelsAndAnnotationsBody(alert)...)
+		}
+	} else {
+		for i, body := range result.Body {
+			b := Body{
+				Type:  "TextBlock",
+				Text:  body,
+				Wrap:  true,
+				Color: colorGrey,
+			}
+			if i < len(alerts) {
+				if alerts[i].Resolved() {
+					b.Color = colorGreen
+				} else {
+					b.Color = colorRed
+				}
+			}
+			blocks = append(blocks, b)
+		}
+	}
+
+	return blocks, nil
+}
+
 func (*Notifier) createLabelsAndAnnotationsBody(alert *types.Alert) []Body {
 	bodies := []Body{}
 	bodies = append(bodies, Body{

pkg/alertmanager/alertmanagernotify/msteamsv2/msteamsv2_test.go

@@ -17,6 +17,7 @@ import (
 	"context"
 	"encoding/json"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -24,6 +25,12 @@ import (
 	"testing"
 	"time"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertnotificationprocessor"
+	"github.com/SigNoz/signoz/pkg/emailing/templatestore/filetemplatestore"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/promslog"
@@ -32,21 +39,31 @@ import (
 	test "github.com/SigNoz/signoz/pkg/alertmanager/alertmanagernotify/alertmanagernotifytest"
 	"github.com/prometheus/alertmanager/config"
 	"github.com/prometheus/alertmanager/notify"
+	"github.com/prometheus/alertmanager/template"
 	"github.com/prometheus/alertmanager/types"
 )
 
+func newTestProcessor(tmpl *template.Template) alertmanagertypes.NotificationProcessor {
+	logger := slog.Default()
+	templater := alertmanagertemplate.New(tmpl, logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(logger)
+	return alertnotificationprocessor.New(templater, renderer, filetemplatestore.NewEmptyStore(), logger)
+}
+
 // This is a test URL that has been modified to not be valid.
 var testWebhookURL, _ = url.Parse("https://example.westeurope.logic.azure.com:443/workflows/xxx/triggers/manual/paths/invoke?api-version=2016-06-01&sp=%2Ftriggers%2Fmanual%2Frun&sv=1.0&sig=xxx")
 
 func TestMSTeamsV2Retry(t *testing.T) {
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.MSTeamsV2Config{
 			WebhookURL: &config.SecretURL{URL: testWebhookURL},
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		`{{ template "msteamsv2.default.titleLink" . }}`,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -73,14 +90,16 @@ func TestNotifier_Notify_WithReason(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			tmpl := test.CreateTmpl(t)
 			notifier, err := New(
 				&config.MSTeamsV2Config{
 					WebhookURL: &config.SecretURL{URL: testWebhookURL},
 					HTTPConfig: &commoncfg.HTTPClientConfig{},
 				},
-				test.CreateTmpl(t),
+				tmpl,
 				`{{ template "msteamsv2.default.titleLink" . }}`,
 				promslog.NewNopLogger(),
+				newTestProcessor(tmpl),
 			)
 			require.NoError(t, err)
 
@@ -162,7 +181,8 @@ func TestMSTeamsV2Templating(t *testing.T) {
 		t.Run(tc.title, func(t *testing.T) {
 			tc.cfg.WebhookURL = &config.SecretURL{URL: u}
 			tc.cfg.HTTPConfig = &commoncfg.HTTPClientConfig{}
-			pd, err := New(tc.cfg, test.CreateTmpl(t), tc.titleLink, promslog.NewNopLogger())
+			tmpl := test.CreateTmpl(t)
+			pd, err := New(tc.cfg, tmpl, tc.titleLink, promslog.NewNopLogger(), newTestProcessor(tmpl))
 			require.NoError(t, err)
 
 			ctx := context.Background()
@@ -195,20 +215,124 @@ func TestMSTeamsV2RedactedURL(t *testing.T) {
 	defer fn()
 
 	secret := "secret"
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.MSTeamsV2Config{
 			WebhookURL: &config.SecretURL{URL: u},
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		`{{ template "msteamsv2.default.titleLink" . }}`,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
 	test.AssertNotifyLeaksNoSecret(ctx, t, notifier, secret)
 }
 
+func TestPrepareContent(t *testing.T) {
+	t.Run("default template - firing alerts", func(t *testing.T) {
+		tmpl := test.CreateTmpl(t)
+		notifier, err := New(
+			&config.MSTeamsV2Config{
+				WebhookURL: &config.SecretURL{URL: testWebhookURL},
+				HTTPConfig: &commoncfg.HTTPClientConfig{},
+				Title:      "Alertname: {{ .CommonLabels.alertname }}",
+			},
+			tmpl,
+			`{{ template "msteamsv2.default.titleLink" . }}`,
+			promslog.NewNopLogger(),
+			newTestProcessor(tmpl),
+		)
+		require.NoError(t, err)
+
+		ctx := context.Background()
+		ctx = notify.WithGroupKey(ctx, "1")
+
+		alerts := []*types.Alert{
+			{
+				Alert: model.Alert{
+					Labels: model.LabelSet{"alertname": "test"},
+					// Custom body template
+					Annotations: model.LabelSet{
+						ruletypes.AnnotationBodyTemplate: "Firing alert: $alertname",
+					},
+					StartsAt: time.Now(),
+					EndsAt:   time.Now().Add(time.Hour),
+				},
+			},
+		}
+		blocks, err := notifier.prepareContent(ctx, alerts)
+		require.NoError(t, err)
+		require.NotEmpty(t, blocks)
+		// First block should be the title with color (firing = red)
+		require.Equal(t, "Bolder", blocks[0].Weight)
+		require.Equal(t, colorRed, blocks[0].Color)
+		// verify title text
+		require.Equal(t, "Alertname: test", blocks[0].Text)
+		// verify body text
+		require.Equal(t, "Firing alert: test", blocks[1].Text)
+	})
+
+	t.Run("custom template - per-alert color", func(t *testing.T) {
+		tmpl := test.CreateTmpl(t)
+		notifier, err := New(
+			&config.MSTeamsV2Config{
+				WebhookURL: &config.SecretURL{URL: testWebhookURL},
+				HTTPConfig: &commoncfg.HTTPClientConfig{},
+			},
+			tmpl,
+			`{{ template "msteamsv2.default.titleLink" . }}`,
+			promslog.NewNopLogger(),
+			newTestProcessor(tmpl),
+		)
+		require.NoError(t, err)
+
+		ctx := context.Background()
+		ctx = notify.WithGroupKey(ctx, "1")
+
+		alerts := []*types.Alert{
+			{
+				Alert: model.Alert{
+					Labels: model.LabelSet{"alertname": "test1"},
+					Annotations: model.LabelSet{
+						"summary":                         "test",
+						ruletypes.AnnotationTitleTemplate: "Custom Title",
+						ruletypes.AnnotationBodyTemplate:  "custom body $alertname",
+					},
+					StartsAt: time.Now(),
+					EndsAt:   time.Now().Add(time.Hour),
+				},
+			},
+			{
+				Alert: model.Alert{
+					Labels: model.LabelSet{"alertname": "test2"},
+					Annotations: model.LabelSet{
+						"summary":                         "test",
+						ruletypes.AnnotationTitleTemplate: "Custom Title",
+						ruletypes.AnnotationBodyTemplate:  "custom body $alertname",
+					},
+					StartsAt: time.Now().Add(-time.Hour),
+					EndsAt:   time.Now().Add(-time.Minute),
+				},
+			},
+		}
+		blocks, err := notifier.prepareContent(ctx, alerts)
+		require.NoError(t, err)
+		require.NotEmpty(t, blocks)
+		// total 3 blocks: title and 2 body blocks
+		require.True(t, len(blocks) == 3)
+		// First block: title color is overall color of the alerts
+		require.Equal(t, colorRed, blocks[0].Color)
+		// verify title text
+		require.Equal(t, "Custom Title", blocks[0].Text)
+		// Body blocks should have per-alert color
+		require.Equal(t, colorRed, blocks[1].Color)   // firing
+		require.Equal(t, colorGreen, blocks[2].Color) // resolved
+	})
+}
+
 func TestMSTeamsV2ReadingURLFromFile(t *testing.T) {
 	ctx, u, fn := test.GetContextWithCancelingURL()
 	defer fn()
@@ -218,14 +342,16 @@ func TestMSTeamsV2ReadingURLFromFile(t *testing.T) {
 	_, err = f.WriteString(u.String() + "\n")
 	require.NoError(t, err, "writing to temp file failed")
 
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.MSTeamsV2Config{
 			WebhookURLFile: f.Name(),
 			HTTPConfig:     &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		`{{ template "msteamsv2.default.titleLink" . }}`,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 

pkg/alertmanager/alertmanagernotify/opsgenie/opsgenie.go

@@ -24,7 +24,10 @@ import (
 	"os"
 	"strings"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 
@@ -43,25 +46,27 @@ const maxMessageLenRunes = 130
 
 // Notifier implements a Notifier for OpsGenie notifications.
 type Notifier struct {
-	conf    *config.OpsGenieConfig
-	tmpl    *template.Template
-	logger  *slog.Logger
-	client  *http.Client
-	retrier *notify.Retrier
+	conf      *config.OpsGenieConfig
+	tmpl      *template.Template
+	logger    *slog.Logger
+	client    *http.Client
+	retrier   *notify.Retrier
+	processor alertmanagertypes.NotificationProcessor
 }
 
 // New returns a new OpsGenie notifier.
-func New(c *config.OpsGenieConfig, t *template.Template, l *slog.Logger, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
+func New(c *config.OpsGenieConfig, t *template.Template, l *slog.Logger, proc alertmanagertypes.NotificationProcessor, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
 	client, err := notify.NewClientWithTracing(*c.HTTPConfig, Integration, httpOpts...)
 	if err != nil {
 		return nil, err
 	}
 	return &Notifier{
-		conf:    c,
-		tmpl:    t,
-		logger:  l,
-		client:  client,
-		retrier: &notify.Retrier{RetryCodes: []int{http.StatusTooManyRequests}},
+		conf:      c,
+		tmpl:      t,
+		logger:    l,
+		client:    client,
+		retrier:   &notify.Retrier{RetryCodes: []int{http.StatusTooManyRequests}},
+		processor: proc,
 	}, nil
 }
 
@@ -132,6 +137,47 @@ func safeSplit(s, sep string) []string {
 	return b
 }
 
+// prepareContent extracts custom templates from alert annotations, runs the
+// notification processor, and returns a ready-to-use title (truncated to the
+// OpsGenie 130-rune limit) and description.
+func (n *Notifier) prepareContent(ctx context.Context, alerts []*types.Alert) (string, string, error) {
+	customTitle, customBody := alertmanagertemplate.ExtractTemplatesFromAnnotations(alerts)
+	result, err := n.processor.ProcessAlertNotification(ctx, alertmanagertypes.NotificationProcessorInput{
+		TitleTemplate:        customTitle,
+		BodyTemplate:         customBody,
+		DefaultTitleTemplate: n.conf.Message,
+		DefaultBodyTemplate:  n.conf.Description,
+	}, alerts, markdownrenderer.MarkdownFormatHTML)
+	if err != nil {
+		return "", "", err
+	}
+
+	title := result.Title
+	description := strings.Join(result.Body, "\n")
+
+	if result.IsCustomTemplated() {
+		// OpsGenie uses basic HTML for alert description previews, so we
+		// separate each per-alert body with an <hr> divider.
+		var b strings.Builder
+		for i, part := range result.Body {
+			if i > 0 {
+				b.WriteString("<hr>")
+			}
+			b.WriteString("<div>")
+			b.WriteString(part)
+			b.WriteString("</div>")
+		}
+		description = b.String()
+	}
+
+	title, truncated := notify.TruncateInRunes(title, maxMessageLenRunes)
+	if truncated {
+		n.logger.WarnContext(ctx, "Truncated message", slog.Int("max_runes", maxMessageLenRunes))
+	}
+
+	return title, description, nil
+}
+
 // Create requests for a list of alerts.
 func (n *Notifier) createRequests(ctx context.Context, as ...*types.Alert) ([]*http.Request, bool, error) {
 	key, err := notify.ExtractGroupKey(ctx)
@@ -177,9 +223,10 @@ func (n *Notifier) createRequests(ctx context.Context, as ...*types.Alert) ([]*h
 		}
 		requests = append(requests, req.WithContext(ctx))
 	default:
-		message, truncated := notify.TruncateInRunes(tmpl(n.conf.Message), maxMessageLenRunes)
-		if truncated {
-			logger.WarnContext(ctx, "Truncated message", slog.Any("alert", key), slog.Int("max_runes", maxMessageLenRunes))
+		message, description, err := n.prepareContent(ctx, as)
+		if err != nil {
+			n.logger.ErrorContext(ctx, "failed to prepare notification content", errors.Attr(err))
+			return nil, false, err
 		}
 
 		createEndpointURL := n.conf.APIURL.Copy()
@@ -218,7 +265,7 @@ func (n *Notifier) createRequests(ctx context.Context, as ...*types.Alert) ([]*h
 		msg := &opsGenieCreateMessage{
 			Alias:       alias,
 			Message:     message,
-			Description: tmpl(n.conf.Description),
+			Description: description,
 			Details:     details,
 			Source:      tmpl(n.conf.Source),
 			Responders:  responders,

pkg/alertmanager/alertmanagernotify/opsgenie/opsgenie_test.go

@@ -17,12 +17,19 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"os"
 	"testing"
 	"time"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertnotificationprocessor"
+	"github.com/SigNoz/signoz/pkg/emailing/templatestore/filetemplatestore"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/promslog"
@@ -31,16 +38,26 @@ import (
 	"github.com/prometheus/alertmanager/config"
 	"github.com/prometheus/alertmanager/notify"
 	"github.com/prometheus/alertmanager/notify/test"
+	"github.com/prometheus/alertmanager/template"
 	"github.com/prometheus/alertmanager/types"
 )
 
+func newTestProcessor(tmpl *template.Template) alertmanagertypes.NotificationProcessor {
+	logger := slog.Default()
+	templater := alertmanagertemplate.New(tmpl, logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(logger)
+	return alertnotificationprocessor.New(templater, renderer, filetemplatestore.NewEmptyStore(), logger)
+}
+
 func TestOpsGenieRetry(t *testing.T) {
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.OpsGenieConfig{
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -56,14 +73,16 @@ func TestOpsGenieRedactedURL(t *testing.T) {
 	defer fn()
 
 	key := "key"
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.OpsGenieConfig{
 			APIURL:     &config.URL{URL: u},
 			APIKey:     config.Secret(key),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -81,14 +100,16 @@ func TestGettingOpsGegineApikeyFromFile(t *testing.T) {
 	_, err = f.WriteString(key)
 	require.NoError(t, err, "writing to temp file failed")
 
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.OpsGenieConfig{
 			APIURL:     &config.URL{URL: u},
 			APIKeyFile: f.Name(),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -211,7 +232,7 @@ func TestOpsGenie(t *testing.T) {
 		},
 	} {
 		t.Run(tc.title, func(t *testing.T) {
-			notifier, err := New(tc.cfg, tmpl, logger)
+			notifier, err := New(tc.cfg, tmpl, logger, newTestProcessor(tmpl))
 			require.NoError(t, err)
 
 			ctx := context.Background()
@@ -287,7 +308,7 @@ func TestOpsGenieWithUpdate(t *testing.T) {
 		APIURL:       &config.URL{URL: u},
 		HTTPConfig:   &commoncfg.HTTPClientConfig{},
 	}
-	notifierWithUpdate, err := New(&opsGenieConfigWithUpdate, tmpl, promslog.NewNopLogger())
+	notifierWithUpdate, err := New(&opsGenieConfigWithUpdate, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
 	alert := &types.Alert{
 		Alert: model.Alert{
 			StartsAt: time.Now(),
@@ -330,7 +351,7 @@ func TestOpsGenieApiKeyFile(t *testing.T) {
 		APIURL:     &config.URL{URL: u},
 		HTTPConfig: &commoncfg.HTTPClientConfig{},
 	}
-	notifierWithUpdate, err := New(&opsGenieConfigWithUpdate, tmpl, promslog.NewNopLogger())
+	notifierWithUpdate, err := New(&opsGenieConfigWithUpdate, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
 
 	require.NoError(t, err)
 	requests, _, err := notifierWithUpdate.createRequests(ctx)
@@ -338,6 +359,101 @@ func TestOpsGenieApiKeyFile(t *testing.T) {
 	require.Equal(t, "GenieKey my_secret_api_key", requests[0].Header.Get("Authorization"))
 }
 
+func TestPrepareContent(t *testing.T) {
+	t.Run("default template", func(t *testing.T) {
+		tmpl := test.CreateTmpl(t)
+		logger := promslog.NewNopLogger()
+		proc := newTestProcessor(tmpl)
+
+		notifier := &Notifier{
+			conf: &config.OpsGenieConfig{
+				Message:     `{{ .CommonLabels.Message }}`,
+				Description: `{{ .CommonLabels.Description }}`,
+			},
+			tmpl:      tmpl,
+			logger:    logger,
+			processor: proc,
+		}
+
+		ctx := context.Background()
+		ctx = notify.WithGroupKey(ctx, "1")
+
+		alert := &types.Alert{
+			Alert: model.Alert{
+				Labels: model.LabelSet{
+					"Message":     "Firing alert: test",
+					"Description": "Check runbook for more details",
+				},
+				StartsAt: time.Now(),
+				EndsAt:   time.Now().Add(time.Hour),
+			},
+		}
+
+		alerts := []*types.Alert{alert}
+
+		title, desc, prepErr := notifier.prepareContent(ctx, alerts)
+		require.NoError(t, prepErr)
+		require.Equal(t, "Firing alert: test", title)
+		require.Equal(t, "Check runbook for more details", desc)
+	})
+
+	t.Run("custom template", func(t *testing.T) {
+		tmpl := test.CreateTmpl(t)
+		logger := promslog.NewNopLogger()
+		proc := newTestProcessor(tmpl)
+
+		notifier := &Notifier{
+			conf: &config.OpsGenieConfig{
+				Message:     `{{ .CommonLabels.Message }}`,
+				Description: `{{ .CommonLabels.Description }}`,
+			},
+			tmpl:      tmpl,
+			logger:    logger,
+			processor: proc,
+		}
+
+		ctx := context.Background()
+		ctx = notify.WithGroupKey(ctx, "1")
+
+		alert1 := &types.Alert{
+			Alert: model.Alert{
+				Labels: model.LabelSet{
+					"service":   "payment",
+					"namespace": "potter-the-harry",
+				},
+				Annotations: model.LabelSet{
+					ruletypes.AnnotationTitleTemplate: "High request throughput for $service",
+					ruletypes.AnnotationBodyTemplate:  "Alert firing in NS: $labels.namespace",
+				},
+				StartsAt: time.Now(),
+				EndsAt:   time.Now().Add(time.Hour),
+			},
+		}
+		alert2 := &types.Alert{
+			Alert: model.Alert{
+				Labels: model.LabelSet{
+					"service":   "payment",
+					"namespace": "smart-the-rat",
+				},
+				Annotations: model.LabelSet{
+					ruletypes.AnnotationTitleTemplate: "High request throughput for $service",
+					ruletypes.AnnotationBodyTemplate:  "Alert firing in NS: $labels.namespace",
+				},
+				StartsAt: time.Now(),
+				EndsAt:   time.Now().Add(time.Hour),
+			},
+		}
+
+		alerts := []*types.Alert{alert1, alert2}
+
+		title, desc, err := notifier.prepareContent(ctx, alerts)
+		require.NoError(t, err)
+		require.Equal(t, "High request throughput for payment", title)
+		// Each alert body wrapped in <div>, separated by <hr>
+		require.Equal(t, "<div><p>Alert firing in NS: potter-the-harry</p><p></p></div><hr><div><p>Alert firing in NS: smart-the-rat</p><p></p></div>", desc)
+	})
+}
+
 func readBody(t *testing.T, r *http.Request) string {
 	t.Helper()
 	body, err := io.ReadAll(r.Body)

pkg/alertmanager/alertmanagernotify/pagerduty/pagerduty.go

@@ -24,7 +24,10 @@ import (
 	"os"
 	"strings"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
 	"github.com/alecthomas/units"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
@@ -49,21 +52,22 @@ const (
 
 // Notifier implements a Notifier for PagerDuty notifications.
 type Notifier struct {
-	conf    *config.PagerdutyConfig
-	tmpl    *template.Template
-	logger  *slog.Logger
-	apiV1   string // for tests.
-	client  *http.Client
-	retrier *notify.Retrier
+	conf      *config.PagerdutyConfig
+	tmpl      *template.Template
+	logger    *slog.Logger
+	apiV1     string // for tests.
+	client    *http.Client
+	retrier   *notify.Retrier
+	processor alertmanagertypes.NotificationProcessor
 }
 
 // New returns a new PagerDuty notifier.
-func New(c *config.PagerdutyConfig, t *template.Template, l *slog.Logger, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
+func New(c *config.PagerdutyConfig, t *template.Template, l *slog.Logger, proc alertmanagertypes.NotificationProcessor, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
 	client, err := notify.NewClientWithTracing(*c.HTTPConfig, Integration, httpOpts...)
 	if err != nil {
 		return nil, err
 	}
-	n := &Notifier{conf: c, tmpl: t, logger: l, client: client}
+	n := &Notifier{conf: c, tmpl: t, logger: l, client: client, processor: proc}
 	if c.ServiceKey != "" || c.ServiceKeyFile != "" {
 		n.apiV1 = "https://events.pagerduty.com/generic/2010-04-15/create_event.json"
 		// Retrying can solve the issue on 403 (rate limiting) and 5xx response codes.
@@ -152,11 +156,12 @@ func (n *Notifier) notifyV1(
 	key notify.Key,
 	data *template.Data,
 	details map[string]any,
+	title string,
 ) (bool, error) {
 	var tmplErr error
 	tmpl := notify.TmplText(n.tmpl, data, &tmplErr)
 
-	description, truncated := notify.TruncateInRunes(tmpl(n.conf.Description), maxV1DescriptionLenRunes)
+	description, truncated := notify.TruncateInRunes(title, maxV1DescriptionLenRunes)
 	if truncated {
 		n.logger.WarnContext(ctx, "Truncated description", slog.Any("key", key), slog.Int("max_runes", maxV1DescriptionLenRunes))
 	}
@@ -212,6 +217,7 @@ func (n *Notifier) notifyV2(
 	key notify.Key,
 	data *template.Data,
 	details map[string]any,
+	title string,
 ) (bool, error) {
 	var tmplErr error
 	tmpl := notify.TmplText(n.tmpl, data, &tmplErr)
@@ -220,7 +226,7 @@ func (n *Notifier) notifyV2(
 		n.conf.Severity = "error"
 	}
 
-	summary, truncated := notify.TruncateInRunes(tmpl(n.conf.Description), maxV2SummaryLenRunes)
+	summary, truncated := notify.TruncateInRunes(title, maxV2SummaryLenRunes)
 	if truncated {
 		n.logger.WarnContext(ctx, "Truncated summary", slog.Any("key", key), slog.Int("max_runes", maxV2SummaryLenRunes))
 	}
@@ -303,6 +309,22 @@ func (n *Notifier) notifyV2(
 	return retry, err
 }
 
+// prepareContent extracts custom templates from alert annotations, runs the
+// notification processor, and returns the processed title ready for use.
+func (n *Notifier) prepareContent(ctx context.Context, alerts []*types.Alert) (string, error) {
+	customTitle, _ := alertmanagertemplate.ExtractTemplatesFromAnnotations(alerts)
+	result, err := n.processor.ProcessAlertNotification(ctx, alertmanagertypes.NotificationProcessorInput{
+		TitleTemplate:        customTitle,
+		DefaultTitleTemplate: n.conf.Description,
+		BodyTemplate:         alertmanagertypes.NoOpTemplateString,
+		DefaultBodyTemplate:  alertmanagertypes.NoOpTemplateString,
+	}, alerts, markdownrenderer.MarkdownFormatNoop)
+	if err != nil {
+		return "", err
+	}
+	return result.Title, nil
+}
+
 // Notify implements the Notifier interface.
 func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error) {
 	key, err := notify.ExtractGroupKey(ctx)
@@ -334,11 +356,17 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 		ctx = nfCtx
 	}
 
+	title, err := n.prepareContent(ctx, as)
+	if err != nil {
+		n.logger.ErrorContext(ctx, "failed to prepare notification content", errors.Attr(err))
+		return false, err
+	}
+
 	nf := n.notifyV2
 	if n.apiV1 != "" {
 		nf = n.notifyV1
 	}
-	retry, err := nf(ctx, eventType, key, data, details)
+	retry, err := nf(ctx, eventType, key, data, details, title)
 	if err != nil {
 		if ctx.Err() != nil {
 			err = errors.WrapInternalf(err, errors.CodeInternal, "failed to notify PagerDuty: %v", context.Cause(ctx))

pkg/alertmanager/alertmanagernotify/pagerduty/pagerduty_test.go

@@ -18,6 +18,7 @@ import (
 	"context"
 	"encoding/json"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -26,7 +27,13 @@ import (
 	"testing"
 	"time"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertnotificationprocessor"
+	"github.com/SigNoz/signoz/pkg/emailing/templatestore/filetemplatestore"
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/promslog"
@@ -39,14 +46,23 @@ import (
 	"github.com/prometheus/alertmanager/types"
 )
 
+func newTestProcessor(tmpl *template.Template) alertmanagertypes.NotificationProcessor {
+	logger := slog.Default()
+	templater := alertmanagertemplate.New(tmpl, logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(logger)
+	return alertnotificationprocessor.New(templater, renderer, filetemplatestore.NewEmptyStore(), logger)
+}
+
 func TestPagerDutyRetryV1(t *testing.T) {
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.PagerdutyConfig{
 			ServiceKey: config.Secret("01234567890123456789012345678901"),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -58,13 +74,15 @@ func TestPagerDutyRetryV1(t *testing.T) {
 }
 
 func TestPagerDutyRetryV2(t *testing.T) {
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.PagerdutyConfig{
 			RoutingKey: config.Secret("01234567890123456789012345678901"),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -80,13 +98,15 @@ func TestPagerDutyRedactedURLV1(t *testing.T) {
 	defer fn()
 
 	key := "01234567890123456789012345678901"
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.PagerdutyConfig{
 			ServiceKey: config.Secret(key),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 	notifier.apiV1 = u.String()
@@ -99,14 +119,16 @@ func TestPagerDutyRedactedURLV2(t *testing.T) {
 	defer fn()
 
 	key := "01234567890123456789012345678901"
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.PagerdutyConfig{
 			URL:        &config.URL{URL: u},
 			RoutingKey: config.Secret(key),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -123,13 +145,15 @@ func TestPagerDutyV1ServiceKeyFromFile(t *testing.T) {
 	ctx, u, fn := test.GetContextWithCancelingURL()
 	defer fn()
 
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.PagerdutyConfig{
 			ServiceKeyFile: f.Name(),
 			HTTPConfig:     &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 	notifier.apiV1 = u.String()
@@ -147,14 +171,16 @@ func TestPagerDutyV2RoutingKeyFromFile(t *testing.T) {
 	ctx, u, fn := test.GetContextWithCancelingURL()
 	defer fn()
 
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.PagerdutyConfig{
 			URL:            &config.URL{URL: u},
 			RoutingKeyFile: f.Name(),
 			HTTPConfig:     &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -311,7 +337,8 @@ func TestPagerDutyTemplating(t *testing.T) {
 		t.Run(tc.title, func(t *testing.T) {
 			tc.cfg.URL = &config.URL{URL: u}
 			tc.cfg.HTTPConfig = &commoncfg.HTTPClientConfig{}
-			pd, err := New(tc.cfg, test.CreateTmpl(t), promslog.NewNopLogger())
+			tmpl := test.CreateTmpl(t)
+			pd, err := New(tc.cfg, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
 			require.NoError(t, err)
 			if pd.apiV1 != "" {
 				pd.apiV1 = u.String()
@@ -401,13 +428,15 @@ func TestEventSizeEnforcement(t *testing.T) {
 		Details:    bigDetailsV1,
 	}
 
+	tmpl := test.CreateTmpl(t)
 	notifierV1, err := New(
 		&config.PagerdutyConfig{
 			ServiceKey: config.Secret("01234567890123456789012345678901"),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -429,8 +458,9 @@ func TestEventSizeEnforcement(t *testing.T) {
 			RoutingKey: config.Secret("01234567890123456789012345678901"),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -545,7 +575,8 @@ func TestPagerDutyEmptySrcHref(t *testing.T) {
 		Links:      links,
 	}
 
-	pagerDuty, err := New(&pagerDutyConfig, test.CreateTmpl(t), promslog.NewNopLogger())
+	pdTmpl := test.CreateTmpl(t)
+	pagerDuty, err := New(&pagerDutyConfig, pdTmpl, promslog.NewNopLogger(), newTestProcessor(pdTmpl))
 	require.NoError(t, err)
 
 	ctx := context.Background()
@@ -612,7 +643,8 @@ func TestPagerDutyTimeout(t *testing.T) {
 				Timeout:    tt.timeout,
 			}
 
-			pd, err := New(&cfg, test.CreateTmpl(t), promslog.NewNopLogger())
+			tmpl := test.CreateTmpl(t)
+			pd, err := New(&cfg, tmpl, promslog.NewNopLogger(), newTestProcessor(tmpl))
 			require.NoError(t, err)
 
 			ctx := context.Background()
@@ -890,3 +922,79 @@ func TestRenderDetails(t *testing.T) {
 		})
 	}
 }
+
+func TestPrepareContent(t *testing.T) {
+	prepareContext := func() context.Context {
+		ctx := context.Background()
+		ctx = notify.WithGroupKey(ctx, "1")
+		ctx = notify.WithReceiverName(ctx, "test-receiver")
+		ctx = notify.WithGroupLabels(ctx, model.LabelSet{"alertname": "HighCPU for Payment service"})
+		return ctx
+	}
+	t.Run("default template uses go text template config for title", func(t *testing.T) {
+		tmpl := test.CreateTmpl(t)
+		notifier, err := New(
+			&config.PagerdutyConfig{
+				RoutingKey:  config.Secret("01234567890123456789012345678901"),
+				HTTPConfig:  &commoncfg.HTTPClientConfig{},
+				Description: `{{ .CommonLabels.alertname }} ({{ .Status | toUpper }})`,
+			},
+			tmpl,
+			promslog.NewNopLogger(),
+			newTestProcessor(tmpl),
+		)
+		require.NoError(t, err)
+
+		ctx := prepareContext()
+
+		alerts := []*types.Alert{
+			{
+				Alert: model.Alert{
+					Labels:   model.LabelSet{"alertname": "HighCPU for Payment service"},
+					StartsAt: time.Now(),
+					EndsAt:   time.Now().Add(time.Hour),
+				},
+			},
+		}
+
+		title, err := notifier.prepareContent(ctx, alerts)
+		require.NoError(t, err)
+		require.Equal(t, "HighCPU for Payment service (FIRING)", title)
+	})
+
+	t.Run("custom template uses $variable annotation for title", func(t *testing.T) {
+		tmpl := test.CreateTmpl(t)
+		notifier, err := New(
+			&config.PagerdutyConfig{
+				RoutingKey: config.Secret("01234567890123456789012345678901"),
+				HTTPConfig: &commoncfg.HTTPClientConfig{},
+			},
+			tmpl,
+			promslog.NewNopLogger(),
+			newTestProcessor(tmpl),
+		)
+		require.NoError(t, err)
+
+		ctx := prepareContext()
+
+		alerts := []*types.Alert{
+			{
+				Alert: model.Alert{
+					Labels: model.LabelSet{
+						"alertname": "HighCPU",
+						"service":   "api-server",
+					},
+					Annotations: model.LabelSet{
+						ruletypes.AnnotationTitleTemplate: "$rule_name on $service is in $status state",
+					},
+					StartsAt: time.Now().Add(-time.Hour),
+					EndsAt:   time.Now(),
+				},
+			},
+		}
+
+		title, err := notifier.prepareContent(ctx, alerts)
+		require.NoError(t, err)
+		require.Equal(t, "HighCPU on api-server is in resolved state", title)
+	})
+}

pkg/alertmanager/alertmanagernotify/receiver.go

@@ -26,7 +26,7 @@ var customNotifierIntegrations = []string{
 	msteamsv2.Integration,
 }
 
-func NewReceiverIntegrations(nc alertmanagertypes.Receiver, tmpl *template.Template, logger *slog.Logger) ([]notify.Integration, error) {
+func NewReceiverIntegrations(nc alertmanagertypes.Receiver, tmpl *template.Template, logger *slog.Logger, proc alertmanagertypes.NotificationProcessor) ([]notify.Integration, error) {
 	upstreamIntegrations, err := receiver.BuildReceiverIntegrations(nc, tmpl, logger)
 	if err != nil {
 		return nil, err
@@ -53,23 +53,23 @@ func NewReceiverIntegrations(nc alertmanagertypes.Receiver, tmpl *template.Templ
 	}
 
 	for i, c := range nc.WebhookConfigs {
-		add(webhook.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return webhook.New(c, tmpl, l) })
+		add(webhook.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return webhook.New(c, tmpl, l, proc) })
 	}
 	for i, c := range nc.EmailConfigs {
-		add(email.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return email.New(c, tmpl, l), nil })
+		add(email.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return email.New(c, tmpl, l, proc), nil })
 	}
 	for i, c := range nc.PagerdutyConfigs {
-		add(pagerduty.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return pagerduty.New(c, tmpl, l) })
+		add(pagerduty.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return pagerduty.New(c, tmpl, l, proc) })
 	}
 	for i, c := range nc.OpsGenieConfigs {
-		add(opsgenie.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return opsgenie.New(c, tmpl, l) })
+		add(opsgenie.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return opsgenie.New(c, tmpl, l, proc) })
 	}
 	for i, c := range nc.SlackConfigs {
-		add(slack.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return slack.New(c, tmpl, l) })
+		add(slack.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) { return slack.New(c, tmpl, l, proc) })
 	}
 	for i, c := range nc.MSTeamsV2Configs {
 		add(msteamsv2.Integration, i, c, func(l *slog.Logger) (notify.Notifier, error) {
-			return msteamsv2.New(c, tmpl, `{{ template "msteamsv2.default.titleLink" . }}`, l)
+			return msteamsv2.New(c, tmpl, `{{ template "msteamsv2.default.titleLink" . }}`, l, proc)
 		})
 	}
 

pkg/alertmanager/alertmanagernotify/slack/slack.go

@@ -23,7 +23,11 @@ import (
 	"os"
 	"strings"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	commoncfg "github.com/prometheus/common/config"
 
 	"github.com/prometheus/alertmanager/config"
@@ -34,6 +38,8 @@ import (
 
 const (
 	Integration = "slack"
+	colorRed    = "#FF0000"
+	colorGreen  = "#00FF00"
 )
 
 // https://api.slack.com/reference/messaging/attachments#legacy_fields - 1024, no units given, assuming runes or characters.
@@ -41,17 +47,18 @@ const maxTitleLenRunes = 1024
 
 // Notifier implements a Notifier for Slack notifications.
 type Notifier struct {
-	conf    *config.SlackConfig
-	tmpl    *template.Template
-	logger  *slog.Logger
-	client  *http.Client
-	retrier *notify.Retrier
+	conf      *config.SlackConfig
+	tmpl      *template.Template
+	logger    *slog.Logger
+	client    *http.Client
+	retrier   *notify.Retrier
+	processor alertmanagertypes.NotificationProcessor
 
 	postJSONFunc func(ctx context.Context, client *http.Client, url string, body io.Reader) (*http.Response, error)
 }
 
 // New returns a new Slack notification handler.
-func New(c *config.SlackConfig, t *template.Template, l *slog.Logger, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
+func New(c *config.SlackConfig, t *template.Template, l *slog.Logger, proc alertmanagertypes.NotificationProcessor, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
 	client, err := notify.NewClientWithTracing(*c.HTTPConfig, Integration, httpOpts...)
 	if err != nil {
 		return nil, err
@@ -63,6 +70,7 @@ func New(c *config.SlackConfig, t *template.Template, l *slog.Logger, httpOpts .
 		logger:       l,
 		client:       client,
 		retrier:      &notify.Retrier{},
+		processor:    proc,
 		postJSONFunc: notify.PostJSON,
 	}, nil
 }
@@ -90,9 +98,10 @@ type attachment struct {
 	Actions    []config.SlackAction `json:"actions,omitempty"`
 	ImageURL   string               `json:"image_url,omitempty"`
 	ThumbURL   string               `json:"thumb_url,omitempty"`
-	Footer     string               `json:"footer"`
+	Footer     string               `json:"footer,omitempty"`
 	Color      string               `json:"color,omitempty"`
 	MrkdwnIn   []string             `json:"mrkdwn_in,omitempty"`
+	Blocks     []any                `json:"blocks,omitempty"`
 }
 
 // Notify implements the Notifier interface.
@@ -109,79 +118,15 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 		data     = notify.GetTemplateData(ctx, n.tmpl, as, logger)
 		tmplText = notify.TmplText(n.tmpl, data, &err)
 	)
-	var markdownIn []string
 
-	if len(n.conf.MrkdwnIn) == 0 {
-		markdownIn = []string{"fallback", "pretext", "text"}
-	} else {
-		markdownIn = n.conf.MrkdwnIn
+	attachments, err := n.prepareContent(ctx, as, tmplText)
+	if err != nil {
+		n.logger.ErrorContext(ctx, "failed to prepare notification content", errors.Attr(err))
+		return false, err
 	}
 
-	title, truncated := notify.TruncateInRunes(tmplText(n.conf.Title), maxTitleLenRunes)
-	if truncated {
-		logger.WarnContext(ctx, "Truncated title", slog.Int("max_runes", maxTitleLenRunes))
-	}
-	att := &attachment{
-		Title:      title,
-		TitleLink:  tmplText(n.conf.TitleLink),
-		Pretext:    tmplText(n.conf.Pretext),
-		Text:       tmplText(n.conf.Text),
-		Fallback:   tmplText(n.conf.Fallback),
-		CallbackID: tmplText(n.conf.CallbackID),
-		ImageURL:   tmplText(n.conf.ImageURL),
-		ThumbURL:   tmplText(n.conf.ThumbURL),
-		Footer:     tmplText(n.conf.Footer),
-		Color:      tmplText(n.conf.Color),
-		MrkdwnIn:   markdownIn,
-	}
-
-	numFields := len(n.conf.Fields)
-	if numFields > 0 {
-		fields := make([]config.SlackField, numFields)
-		for index, field := range n.conf.Fields {
-			// Check if short was defined for the field otherwise fallback to the global setting
-			var short bool
-			if field.Short != nil {
-				short = *field.Short
-			} else {
-				short = n.conf.ShortFields
-			}
-
-			// Rebuild the field by executing any templates and setting the new value for short
-			fields[index] = config.SlackField{
-				Title: tmplText(field.Title),
-				Value: tmplText(field.Value),
-				Short: &short,
-			}
-		}
-		att.Fields = fields
-	}
-
-	numActions := len(n.conf.Actions)
-	if numActions > 0 {
-		actions := make([]config.SlackAction, numActions)
-		for index, action := range n.conf.Actions {
-			slackAction := config.SlackAction{
-				Type:  tmplText(action.Type),
-				Text:  tmplText(action.Text),
-				URL:   tmplText(action.URL),
-				Style: tmplText(action.Style),
-				Name:  tmplText(action.Name),
-				Value: tmplText(action.Value),
-			}
-
-			if action.ConfirmField != nil {
-				slackAction.ConfirmField = &config.SlackConfirmationField{
-					Title:       tmplText(action.ConfirmField.Title),
-					Text:        tmplText(action.ConfirmField.Text),
-					OkText:      tmplText(action.ConfirmField.OkText),
-					DismissText: tmplText(action.ConfirmField.DismissText),
-				}
-			}
-
-			actions[index] = slackAction
-		}
-		att.Actions = actions
+	if len(attachments) > 0 {
+		n.addFieldsAndActions(&attachments[0], tmplText)
 	}
 
 	req := &request{
@@ -191,7 +136,7 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 		IconURL:     tmplText(n.conf.IconURL),
 		LinkNames:   n.conf.LinkNames,
 		Text:        tmplText(n.conf.MessageText),
-		Attachments: []attachment{*att},
+		Attachments: attachments,
 	}
 	if err != nil {
 		return false, err
@@ -247,6 +192,149 @@ func (n *Notifier) Notify(ctx context.Context, as ...*types.Alert) (bool, error)
 	return retry, nil
 }
 
+// prepareContent extracts custom templates from alert annotations, runs the
+// notification processor, and returns the Slack attachment(s) ready to send.
+func (n *Notifier) prepareContent(ctx context.Context, alerts []*types.Alert, tmplText func(string) string) ([]attachment, error) {
+	// Extract custom templates and process them
+	customTitle, customBody := alertmanagertemplate.ExtractTemplatesFromAnnotations(alerts)
+	result, err := n.processor.ProcessAlertNotification(ctx, alertmanagertypes.NotificationProcessorInput{
+		TitleTemplate:        customTitle,
+		BodyTemplate:         customBody,
+		DefaultTitleTemplate: n.conf.Title,
+		// use default body templating to prepare the attachment
+		// as default template uses plain text markdown rendering instead of blockkit
+		DefaultBodyTemplate: alertmanagertypes.NoOpTemplateString,
+	}, alerts, markdownrenderer.MarkdownFormatSlackMrkdwn)
+	if err != nil {
+		return nil, err
+	}
+
+	title, truncated := notify.TruncateInRunes(result.Title, maxTitleLenRunes)
+	if truncated {
+		n.logger.WarnContext(ctx, "Truncated title", slog.Int("max_runes", maxTitleLenRunes))
+	}
+
+	if result.IsDefaultTemplatedBody {
+		var markdownIn []string
+		if len(n.conf.MrkdwnIn) == 0 {
+			markdownIn = []string{"fallback", "pretext", "text"}
+		} else {
+			markdownIn = n.conf.MrkdwnIn
+		}
+		attachments := []attachment{
+			{
+				Title:      title,
+				TitleLink:  tmplText(n.conf.TitleLink),
+				Pretext:    tmplText(n.conf.Pretext),
+				Text:       tmplText(n.conf.Text),
+				Fallback:   tmplText(n.conf.Fallback),
+				CallbackID: tmplText(n.conf.CallbackID),
+				ImageURL:   tmplText(n.conf.ImageURL),
+				ThumbURL:   tmplText(n.conf.ThumbURL),
+				Footer:     tmplText(n.conf.Footer),
+				Color:      tmplText(n.conf.Color),
+				MrkdwnIn:   markdownIn,
+			},
+		}
+		return attachments, nil
+	}
+
+	// Custom template path: one title attachment + one attachment per alert body.
+	// Each alert body gets its own attachment so we can set per-alert color
+	// (red for firing, green for resolved).
+	attachments := make([]attachment, 0, 1+len(result.Body))
+
+	// Title-only attachment (no color)
+	attachments = append(attachments, attachment{
+		Title:     title,
+		TitleLink: tmplText(n.conf.TitleLink),
+	})
+
+	for i, body := range result.Body {
+		color := colorRed // red for firing
+		if i < len(alerts) && alerts[i].Resolved() {
+			color = colorGreen // green for resolved
+		}
+
+		// If alert has related logs and traces, add them to the attachment as action buttons
+		var actionButtons []config.SlackAction
+		relatedLogsLink := alerts[i].Annotations[ruletypes.AnnotationRelatedLogs]
+		relatedTracesLink := alerts[i].Annotations[ruletypes.AnnotationRelatedTraces]
+		if relatedLogsLink != "" {
+			actionButtons = append(actionButtons, config.SlackAction{
+				Type: "button",
+				Text: "View Related Logs",
+				URL:  string(relatedLogsLink),
+			})
+		}
+		if relatedTracesLink != "" {
+			actionButtons = append(actionButtons, config.SlackAction{
+				Type: "button",
+				Text: "View Related Traces",
+				URL:  string(relatedTracesLink),
+			})
+		}
+
+		attachments = append(attachments, attachment{
+			Text:     body,
+			Color:    color,
+			MrkdwnIn: []string{"text"},
+			Actions:  actionButtons,
+		})
+	}
+
+	return attachments, nil
+}
+
+// addFieldsAndActions populates fields and actions on the attachment from the Slack config.
+func (n *Notifier) addFieldsAndActions(att *attachment, tmplText func(string) string) {
+	numFields := len(n.conf.Fields)
+	if numFields > 0 {
+		fields := make([]config.SlackField, numFields)
+		for index, field := range n.conf.Fields {
+			var short bool
+			if field.Short != nil {
+				short = *field.Short
+			} else {
+				short = n.conf.ShortFields
+			}
+			fields[index] = config.SlackField{
+				Title: tmplText(field.Title),
+				Value: tmplText(field.Value),
+				Short: &short,
+			}
+		}
+		att.Fields = fields
+	}
+
+	numActions := len(n.conf.Actions)
+	if numActions > 0 {
+		actions := make([]config.SlackAction, numActions)
+		for index, action := range n.conf.Actions {
+			slackAction := config.SlackAction{
+				Type:  tmplText(action.Type),
+				Text:  tmplText(action.Text),
+				URL:   tmplText(action.URL),
+				Style: tmplText(action.Style),
+				Name:  tmplText(action.Name),
+				Value: tmplText(action.Value),
+			}
+
+			if action.ConfirmField != nil {
+				slackAction.ConfirmField = &config.SlackConfirmationField{
+					Title:       tmplText(action.ConfirmField.Title),
+					Text:        tmplText(action.ConfirmField.Text),
+					OkText:      tmplText(action.ConfirmField.OkText),
+					DismissText: tmplText(action.ConfirmField.DismissText),
+				}
+			}
+
+			actions[index] = slackAction
+		}
+		att.Actions = actions
+	}
+}
+
 // checkResponseError parses out the error message from Slack API response.
 func checkResponseError(resp *http.Response) (bool, error) {
 	body, err := io.ReadAll(resp.Body)

pkg/alertmanager/alertmanagernotify/slack/slack_test.go

@@ -26,6 +26,12 @@ import (
 	"testing"
 	"time"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertnotificationprocessor"
+	"github.com/SigNoz/signoz/pkg/emailing/templatestore/filetemplatestore"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/promslog"
@@ -38,13 +44,22 @@ import (
 	"github.com/prometheus/alertmanager/types"
 )
 
+func newTestProcessor(tmpl *template.Template) alertmanagertypes.NotificationProcessor {
+	logger := slog.Default()
+	templater := alertmanagertemplate.New(tmpl, logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(logger)
+	return alertnotificationprocessor.New(templater, renderer, filetemplatestore.NewEmptyStore(), logger)
+}
+
 func TestSlackRetry(t *testing.T) {
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.SlackConfig{
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -58,13 +73,15 @@ func TestSlackRedactedURL(t *testing.T) {
 	ctx, u, fn := test.GetContextWithCancelingURL()
 	defer fn()
 
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.SlackConfig{
 			APIURL:     &config.SecretURL{URL: u},
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -80,13 +97,15 @@ func TestGettingSlackURLFromFile(t *testing.T) {
 	_, err = f.WriteString(u.String())
 	require.NoError(t, err, "writing to temp file failed")
 
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.SlackConfig{
 			APIURLFile: f.Name(),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -102,13 +121,15 @@ func TestTrimmingSlackURLFromFile(t *testing.T) {
 	_, err = f.WriteString(u.String() + "\n\n")
 	require.NoError(t, err, "writing to temp file failed")
 
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.SlackConfig{
 			APIURLFile: f.Name(),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -193,6 +214,7 @@ func TestNotifier_Notify_WithReason(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			apiurl, _ := url.Parse("https://slack.com/post.Message")
+			tmpl := test.CreateTmpl(t)
 			notifier, err := New(
 				&config.SlackConfig{
 					NotifierConfig: config.NotifierConfig{},
@@ -200,8 +222,9 @@ func TestNotifier_Notify_WithReason(t *testing.T) {
 					APIURL:         &config.SecretURL{URL: apiurl},
 					Channel:        "channelname",
 				},
-				test.CreateTmpl(t),
+				tmpl,
 				promslog.NewNopLogger(),
+				newTestProcessor(tmpl),
 			)
 			require.NoError(t, err)
 
@@ -251,6 +274,7 @@ func TestSlackTimeout(t *testing.T) {
 	for name, tt := range tests {
 		t.Run(name, func(t *testing.T) {
 			u, _ := url.Parse("https://slack.com/post.Message")
+			tmpl := test.CreateTmpl(t)
 			notifier, err := New(
 				&config.SlackConfig{
 					NotifierConfig: config.NotifierConfig{},
@@ -259,8 +283,9 @@ func TestSlackTimeout(t *testing.T) {
 					Channel:        "channelname",
 					Timeout:        tt.timeout,
 				},
-				test.CreateTmpl(t),
+				tmpl,
 				promslog.NewNopLogger(),
+				newTestProcessor(tmpl),
 			)
 			require.NoError(t, err)
 			notifier.postJSONFunc = func(ctx context.Context, client *http.Client, url string, body io.Reader) (*http.Response, error) {
@@ -291,6 +316,225 @@ func TestSlackTimeout(t *testing.T) {
 	}
 }
 
+// setupTestContext creates a context with group key, receiver name, and group labels
+// required by the notification processor.
+func setupTestContext() context.Context {
+	ctx := context.Background()
+	ctx = notify.WithGroupKey(ctx, "test-group")
+	ctx = notify.WithReceiverName(ctx, "slack")
+	ctx = notify.WithGroupLabels(ctx, model.LabelSet{
+		"alertname": "TestAlert",
+		"severity":  "critical",
+	})
+	return ctx
+}
+
+func TestPrepareContent(t *testing.T) {
+	t.Run("default template uses go text template config for title and body", func(t *testing.T) {
+		// When alerts have no custom annotation templates (title_template / body_template),
+		tmpl := test.CreateTmpl(t)
+		proc := newTestProcessor(tmpl)
+		notifier := &Notifier{
+			conf: &config.SlackConfig{
+				Title:     `{{ .CommonLabels.alertname }} ({{ .Status | toUpper }})`,
+				Text:      `{{ range .Alerts }}Alert: {{ .Labels.alertname }} - severity {{ .Labels.severity }}{{ end }}`,
+				Color:     `{{ if eq .Status "firing" }}danger{{ else }}good{{ end }}`,
+				TitleLink: "https://alertmanager.signoz.com",
+			},
+			tmpl:      tmpl,
+			logger:    slog.New(slog.DiscardHandler),
+			processor: proc,
+		}
+
+		ctx := setupTestContext()
+		alerts := []*types.Alert{
+			{Alert: model.Alert{
+				Labels:   model.LabelSet{ruletypes.LabelAlertName: "HighCPU", ruletypes.LabelSeverityName: "critical"},
+				StartsAt: time.Now(),
+				EndsAt:   time.Now().Add(time.Hour),
+			}},
+		}
+
+		// Build tmplText the same way Notify does
+		var err error
+		data := notify.GetTemplateData(ctx, tmpl, alerts, slog.New(slog.DiscardHandler))
+		tmplText := notify.TmplText(tmpl, data, &err)
+
+		atts, attErr := notifier.prepareContent(ctx, alerts, tmplText)
+		require.NoError(t, attErr)
+		require.NoError(t, err)
+		require.Len(t, atts, 1)
+
+		require.Equal(t, "HighCPU (FIRING)", atts[0].Title)
+		require.Equal(t, "Alert: HighCPU - severity critical", atts[0].Text)
+		// Color is templated — firing alert should be "danger"
+		require.Equal(t, "danger", atts[0].Color)
+		// No BlockKit blocks for default template
+		require.Nil(t, atts[0].Blocks)
+		// Default markdownIn when config has none
+		require.Equal(t, []string{"fallback", "pretext", "text"}, atts[0].MrkdwnIn)
+	})
+
+	t.Run("custom template produces 1+N attachments with per-alert color", func(t *testing.T) {
+		// When alerts carry custom $variable annotation templates (title_template / body_template)
+		tmpl := test.CreateTmpl(t)
+		proc := newTestProcessor(tmpl)
+		notifier := &Notifier{
+			conf: &config.SlackConfig{
+				Title:     "default title fallback",
+				Text:      "default text fallback",
+				TitleLink: "https://alertmanager.signoz.com",
+			},
+			tmpl:      tmpl,
+			logger:    slog.New(slog.DiscardHandler),
+			processor: proc,
+		}
+		tmplText := func(s string) string { return s }
+
+		bodyTemplate := `## $rule_name
+
+**Service:** *$labels.service*
+**Instance:** *$labels.instance*
+**Region:** *$labels.region*
+**Method:** *$labels.http_method*
+
+---
+
+| Metric | Value |
+|--------|-------|
+| **Current** | *$value* |
+| **Threshold** | *$threshold* |
+
+**Status:** $status | **Severity:** $severity`
+		titleTemplate := "[$status] $rule_name — $labels.service"
+
+		ctx := setupTestContext()
+		firingAlert := &types.Alert{
+			Alert: model.Alert{
+				Labels:   model.LabelSet{ruletypes.LabelAlertName: "HighCPU", ruletypes.LabelSeverityName: "critical", "service": "api-server", "instance": "i-0abc123", "region": "us-east-1", "http_method": "GET"},
+				StartsAt: time.Now(),
+				EndsAt:   time.Now().Add(time.Hour),
+				Annotations: model.LabelSet{
+					ruletypes.AnnotationTitleTemplate: model.LabelValue(titleTemplate),
+					ruletypes.AnnotationBodyTemplate:  model.LabelValue(bodyTemplate),
+					"value":                           "100",
+					"threshold.value":                 "200",
+				},
+			},
+		}
+		resolvedAlert := &types.Alert{
+			Alert: model.Alert{
+				Labels:   model.LabelSet{ruletypes.LabelAlertName: "HighCPU", ruletypes.LabelSeverityName: "critical", "service": "api-server", "instance": "i-0abc123", "region": "us-east-1", "http_method": "GET"},
+				StartsAt: time.Now().Add(-2 * time.Hour),
+				EndsAt:   time.Now().Add(-time.Hour),
+				Annotations: model.LabelSet{
+					ruletypes.AnnotationTitleTemplate: model.LabelValue(titleTemplate),
+					ruletypes.AnnotationBodyTemplate:  model.LabelValue(bodyTemplate),
+					"value":                           "50",
+					"threshold.value":                 "200",
+				},
+			},
+		}
+
+		atts, err := notifier.prepareContent(ctx, []*types.Alert{firingAlert, resolvedAlert}, tmplText)
+		require.NoError(t, err)
+
+		// 1 title attachment + 2 body attachments (one per alert)
+		require.Len(t, atts, 3)
+
+		// First attachment: title-only, no color, no blocks
+		require.Equal(t, "[firing] HighCPU — api-server", atts[0].Title)
+		require.Empty(t, atts[0].Color)
+		require.Nil(t, atts[0].Blocks)
+		require.Equal(t, "https://alertmanager.signoz.com", atts[0].TitleLink)
+
+		expectedFiringBody := "*HighCPU*\n\n" +
+			"*Service:* _api-server_\n*Instance:* _i-0abc123_\n*Region:* _us-east-1_\n*Method:* _GET_\n\n" +
+			"---\n\n" +
+			"```\nMetric    | Value\n----------|------\nCurrent   | 100  \nThreshold | 200  \n```\n\n" +
+			"*Status:* firing | *Severity:* critical\n\n"
+
+		expectedResolvedBody := "*HighCPU*\n\n" +
+			"*Service:* _api-server_\n*Instance:* _i-0abc123_\n*Region:* _us-east-1_\n*Method:* _GET_\n\n" +
+			"---\n\n" +
+			"```\nMetric    | Value\n----------|------\nCurrent   | 50   \nThreshold | 200  \n```\n\n" +
+			"*Status:* resolved | *Severity:* critical\n\n"
+
+		// Second attachment: firing alert body rendered as slack mrkdwn text, red color
+		require.Nil(t, atts[1].Blocks)
+		require.Equal(t, "#FF0000", atts[1].Color)
+		require.Equal(t, []string{"text"}, atts[1].MrkdwnIn)
+		require.Equal(t, expectedFiringBody, atts[1].Text)
+
+		// Third attachment: resolved alert body rendered as slack mrkdwn text, green color
+		require.Nil(t, atts[2].Blocks)
+		require.Equal(t, "#00FF00", atts[2].Color)
+		require.Equal(t, []string{"text"}, atts[2].MrkdwnIn)
+		require.Equal(t, expectedResolvedBody, atts[2].Text)
+	})
+
+	t.Run("default template with fields and actions", func(t *testing.T) {
+		// Verifies that addFieldsAndActions (called from Notify after prepareContent)
+		// correctly populates fields and actions on the attachment from config.
+		tmpl := test.CreateTmpl(t)
+		proc := newTestProcessor(tmpl)
+		short := true
+		notifier := &Notifier{
+			conf: &config.SlackConfig{
+				Title: `{{ .CommonLabels.alertname }}`,
+				Text:  "alert text",
+				Color: "warning",
+				Fields: []*config.SlackField{
+					{Title: "Severity", Value: "critical", Short: &short},
+					{Title: "Service", Value: "api-server", Short: &short},
+				},
+				Actions: []*config.SlackAction{
+					{Type: "button", Text: "View Alert", URL: "https://alertmanager.signoz.com"},
+				},
+				TitleLink: "https://alertmanager.signoz.com",
+			},
+			tmpl:      tmpl,
+			logger:    slog.New(slog.DiscardHandler),
+			processor: proc,
+		}
+		tmplText := func(s string) string { return s }
+
+		ctx := setupTestContext()
+		alerts := []*types.Alert{
+			{Alert: model.Alert{
+				Labels:   model.LabelSet{ruletypes.LabelAlertName: "TestAlert"},
+				StartsAt: time.Now(),
+				EndsAt:   time.Now().Add(time.Hour),
+			}},
+		}
+		atts, err := notifier.prepareContent(ctx, alerts, tmplText)
+		require.NoError(t, err)
+		require.Len(t, atts, 1)
+
+		// prepareContent does not populate fields/actions — that's done by
+		// addFieldsAndActions which is called from Notify.
+		require.Nil(t, atts[0].Fields)
+		require.Nil(t, atts[0].Actions)
+
+		// Simulate what Notify does after prepareContent
+		notifier.addFieldsAndActions(&atts[0], tmplText)
+
+		// Verify fields
+		require.Len(t, atts[0].Fields, 2)
+		require.Equal(t, "Severity", atts[0].Fields[0].Title)
+		require.Equal(t, "critical", atts[0].Fields[0].Value)
+		require.True(t, *atts[0].Fields[0].Short)
+		require.Equal(t, "Service", atts[0].Fields[1].Title)
+		require.Equal(t, "api-server", atts[0].Fields[1].Value)
+
+		// Verify actions
+		require.Len(t, atts[0].Actions, 1)
+		require.Equal(t, "button", atts[0].Actions[0].Type)
+		require.Equal(t, "View Alert", atts[0].Actions[0].Text)
+		require.Equal(t, "https://alertmanager.signoz.com", atts[0].Actions[0].URL)
+	})
+}
+
 func TestSlackMessageField(t *testing.T) {
 	// 1. Setup a fake Slack server
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -338,7 +582,7 @@ func TestSlackMessageField(t *testing.T) {
 	tmpl.ExternalURL = u
 
 	logger := slog.New(slog.DiscardHandler)
-	notifier, err := New(conf, tmpl, logger)
+	notifier, err := New(conf, tmpl, logger, newTestProcessor(tmpl))
 	if err != nil {
 		t.Fatal(err)
 	}

pkg/alertmanager/alertmanagernotify/webhook/webhook.go

@@ -22,8 +22,13 @@ import (
 	"os"
 	"strings"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	commoncfg "github.com/prometheus/common/config"
+	"github.com/prometheus/common/model"
 
 	"github.com/prometheus/alertmanager/config"
 	"github.com/prometheus/alertmanager/notify"
@@ -37,24 +42,26 @@ const (
 
 // Notifier implements a Notifier for generic webhooks.
 type Notifier struct {
-	conf    *config.WebhookConfig
-	tmpl    *template.Template
-	logger  *slog.Logger
-	client  *http.Client
-	retrier *notify.Retrier
+	conf      *config.WebhookConfig
+	tmpl      *template.Template
+	logger    *slog.Logger
+	client    *http.Client
+	retrier   *notify.Retrier
+	processor alertmanagertypes.NotificationProcessor
 }
 
 // New returns a new Webhook.
-func New(conf *config.WebhookConfig, t *template.Template, l *slog.Logger, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
+func New(conf *config.WebhookConfig, t *template.Template, l *slog.Logger, proc alertmanagertypes.NotificationProcessor, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
 	client, err := notify.NewClientWithTracing(*conf.HTTPConfig, Integration, httpOpts...)
 	if err != nil {
 		return nil, err
 	}
 	return &Notifier{
-		conf:   conf,
-		tmpl:   t,
-		logger: l,
-		client: client,
+		conf:      conf,
+		tmpl:      t,
+		logger:    l,
+		client:    client,
+		processor: proc,
 		// Webhooks are assumed to respond with 2xx response codes on a successful
 		// request and 5xx response codes are assumed to be recoverable.
 		retrier: &notify.Retrier{},
@@ -79,9 +86,45 @@ func truncateAlerts(maxAlerts uint64, alerts []*types.Alert) ([]*types.Alert, ui
 	return alerts, 0
 }
 
+// templateAlerts extracts custom templates from alert annotations, processes them,
+// and updates each alert's annotations with the rendered title and body
+// the idea is to send the templated annotations for title and body templates to the webhook endpoint.
+func (n *Notifier) templateAlerts(ctx context.Context, alerts []*types.Alert) error {
+	customTitle, customBody := alertmanagertemplate.ExtractTemplatesFromAnnotations(alerts)
+	result, err := n.processor.ProcessAlertNotification(ctx, alertmanagertypes.NotificationProcessorInput{
+		TitleTemplate:        customTitle,
+		BodyTemplate:         customBody,
+		DefaultTitleTemplate: alertmanagertypes.NoOpTemplateString,
+		DefaultBodyTemplate:  alertmanagertypes.NoOpTemplateString,
+	}, alerts, markdownrenderer.MarkdownFormatNoop)
+	if err != nil {
+		return err
+	}
+
+	for i, alert := range alerts {
+		if alert.Annotations == nil {
+			continue
+		}
+		// Update title_template annotation with rendered title, only if key exists and result is non-blank
+		if _, ok := alert.Annotations[ruletypes.AnnotationTitleTemplate]; ok && result.Title != "" {
+			alert.Annotations[ruletypes.AnnotationTitleTemplate] = model.LabelValue(result.Title)
+		}
+		// Update body_template annotation with rendered body, only if key exists and result is non-blank
+		if _, ok := alert.Annotations[ruletypes.AnnotationBodyTemplate]; ok && i < len(result.Body) && result.Body[i] != "" {
+			alert.Annotations[ruletypes.AnnotationBodyTemplate] = model.LabelValue(result.Body[i])
+		}
+	}
+
+	return nil
+}
+
 // Notify implements the Notifier interface.
 func (n *Notifier) Notify(ctx context.Context, alerts ...*types.Alert) (bool, error) {
 	alerts, numTruncated := truncateAlerts(n.conf.MaxAlerts, alerts)
+	// template alerts before preparing the notification data
+	if err := n.templateAlerts(ctx, alerts); err != nil {
+		n.logger.ErrorContext(ctx, "failed to prepare notification content", errors.Attr(err))
+	}
 	data := notify.GetTemplateData(ctx, n.tmpl, alerts, n.logger)
 
 	groupKey, err := notify.ExtractGroupKey(ctx)

pkg/alertmanager/alertmanagernotify/webhook/webhook_test.go

@@ -18,12 +18,19 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"os"
 	"testing"
 	"time"
 
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertnotificationprocessor"
+	"github.com/SigNoz/signoz/pkg/emailing/templatestore/filetemplatestore"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
 	commoncfg "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/common/promslog"
@@ -32,17 +39,27 @@ import (
 	"github.com/prometheus/alertmanager/config"
 	"github.com/prometheus/alertmanager/notify"
 	"github.com/prometheus/alertmanager/notify/test"
+	"github.com/prometheus/alertmanager/template"
 	"github.com/prometheus/alertmanager/types"
 )
 
+func newTestProcessor(tmpl *template.Template) alertmanagertypes.NotificationProcessor {
+	logger := slog.Default()
+	templater := alertmanagertemplate.New(tmpl, logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(logger)
+	return alertnotificationprocessor.New(templater, renderer, filetemplatestore.NewEmptyStore(), logger)
+}
+
 func TestWebhookRetry(t *testing.T) {
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.WebhookConfig{
 			URL:        config.SecretTemplateURL("http://example.com"),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	if err != nil {
 		require.NoError(t, err)
@@ -105,13 +122,15 @@ func TestWebhookRedactedURL(t *testing.T) {
 	defer fn()
 
 	secret := "secret"
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.WebhookConfig{
 			URL:        config.SecretTemplateURL(u.String()),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -127,13 +146,15 @@ func TestWebhookReadingURLFromFile(t *testing.T) {
 	_, err = f.WriteString(u.String() + "\n")
 	require.NoError(t, err, "writing to temp file failed")
 
+	tmpl := test.CreateTmpl(t)
 	notifier, err := New(
 		&config.WebhookConfig{
 			URLFile:    f.Name(),
 			HTTPConfig: &commoncfg.HTTPClientConfig{},
 		},
-		test.CreateTmpl(t),
+		tmpl,
 		promslog.NewNopLogger(),
+		newTestProcessor(tmpl),
 	)
 	require.NoError(t, err)
 
@@ -187,13 +208,15 @@ func TestWebhookURLTemplating(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			calledURL = "" // Reset for each test
 
+			tmpl := test.CreateTmpl(t)
 			notifier, err := New(
 				&config.WebhookConfig{
 					URL:        config.SecretTemplateURL(tc.url),
 					HTTPConfig: &commoncfg.HTTPClientConfig{},
 				},
-				test.CreateTmpl(t),
+				tmpl,
 				promslog.NewNopLogger(),
+				newTestProcessor(tmpl),
 			)
 			require.NoError(t, err)
 
@@ -225,3 +248,95 @@ func TestWebhookURLTemplating(t *testing.T) {
 		})
 	}
 }
+
+func TestTemplateAlerts(t *testing.T) {
+	tmpl := test.CreateTmpl(t)
+	proc := newTestProcessor(tmpl)
+
+	notifier, err := New(
+		&config.WebhookConfig{
+			URL:        config.SecretTemplateURL("http://example.com"),
+			HTTPConfig: &commoncfg.HTTPClientConfig{},
+		},
+		tmpl,
+		slog.Default(),
+		proc,
+	)
+	require.NoError(t, err)
+
+	t.Run("annotations are updated with custom title and body templates", func(t *testing.T) {
+		alerts := []*types.Alert{
+			{
+				Alert: model.Alert{
+					Labels: model.LabelSet{
+						"alertname": "TestAlert",
+						"severity":  "critical",
+					},
+					Annotations: model.LabelSet{
+						ruletypes.AnnotationTitleTemplate: "Alert: $labels.alertname",
+						ruletypes.AnnotationBodyTemplate:  "Severity is $labels.severity",
+					},
+					StartsAt: time.Now(),
+					EndsAt:   time.Now().Add(time.Hour),
+				},
+			},
+			{
+				Alert: model.Alert{
+					Labels: model.LabelSet{
+						"alertname": "TestAlert",
+						"severity":  "warning",
+					},
+					Annotations: model.LabelSet{
+						ruletypes.AnnotationTitleTemplate: "Alert: $labels.alertname",
+						ruletypes.AnnotationBodyTemplate:  "Severity is $labels.severity",
+					},
+					StartsAt: time.Now(),
+					EndsAt:   time.Now().Add(time.Hour),
+				},
+			},
+		}
+
+		ctx := context.Background()
+		err := notifier.templateAlerts(ctx, alerts)
+		require.NoError(t, err)
+
+		// Both alerts should have their title_template updated to the rendered title
+		require.Equal(t, model.LabelValue("Alert: TestAlert"), alerts[0].Annotations[ruletypes.AnnotationTitleTemplate])
+		require.Equal(t, model.LabelValue("Alert: TestAlert"), alerts[1].Annotations[ruletypes.AnnotationTitleTemplate])
+		// Each alert should have its own body_template based on its labels
+		require.Equal(t, model.LabelValue("Severity is critical"), alerts[0].Annotations[ruletypes.AnnotationBodyTemplate])
+		require.Equal(t, model.LabelValue("Severity is warning"), alerts[1].Annotations[ruletypes.AnnotationBodyTemplate])
+	})
+
+	t.Run("annotations not updated when template keys are absent", func(t *testing.T) {
+		alerts := []*types.Alert{
+			{
+				Alert: model.Alert{
+					Labels: model.LabelSet{
+						"alertname": "NoTemplateAlert",
+					},
+					Annotations: model.LabelSet{
+						"summary":     "keep this",
+						"description": "keep this too",
+					},
+					StartsAt: time.Now(),
+					EndsAt:   time.Now().Add(time.Hour),
+				},
+			},
+		}
+
+		ctx := context.Background()
+		err := notifier.templateAlerts(ctx, alerts)
+		require.NoError(t, err)
+
+		// title_template and body_template keys should NOT be added
+		_, hasTitleTemplate := alerts[0].Annotations[ruletypes.AnnotationTitleTemplate]
+		_, hasBodyTemplate := alerts[0].Annotations[ruletypes.AnnotationBodyTemplate]
+		require.False(t, hasTitleTemplate, "title_template should not be added when absent")
+		require.False(t, hasBodyTemplate, "body_template should not be added when absent")
+
+		// Existing annotations should remain untouched
+		require.Equal(t, model.LabelValue("keep this"), alerts[0].Annotations["summary"])
+		require.Equal(t, model.LabelValue("keep this too"), alerts[0].Annotations["description"])
+	})
+}

pkg/alertmanager/alertmanagerserver/config.go

@@ -28,6 +28,9 @@ type Config struct {
 
 	// Configuration for the notification log.
 	NFLog NFLogConfig `mapstructure:"nflog"`
+
+	// EmailTemplatesDirectory is the directory containing email layout templates (.gotmpl files).
+	EmailTemplatesDirectory string `mapstructure:"email_templates_directory"`
 }
 
 type AlertsConfig struct {
@@ -100,5 +103,6 @@ func NewConfig() Config {
 			MaintenanceInterval: 15 * time.Minute,
 			Retention:           120 * time.Hour,
 		},
+		EmailTemplatesDirectory: "/root/templates/email",
 	}
 }

pkg/alertmanager/alertmanagerserver/server.go

@@ -10,6 +10,7 @@ import (
 	"github.com/prometheus/alertmanager/types"
 	"golang.org/x/sync/errgroup"
 
+	"github.com/SigNoz/signoz/pkg/errors"
 	"github.com/prometheus/alertmanager/dispatch"
 	"github.com/prometheus/alertmanager/featurecontrol"
 	"github.com/prometheus/alertmanager/inhibit"
@@ -23,9 +24,13 @@ import (
 	"github.com/prometheus/common/model"
 
 	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagernotify"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertnotificationprocessor"
 	"github.com/SigNoz/signoz/pkg/alertmanager/nfmanager"
-	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/emailing/templatestore/filetemplatestore"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
 	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/emailtypes"
 )
 
 var (
@@ -66,6 +71,8 @@ type Server struct {
 	pipelineBuilder     *notify.PipelineBuilder
 	marker              *alertmanagertypes.MemMarker
 	tmpl                *template.Template
+	processor           alertmanagertypes.NotificationProcessor
+	emailTemplateStore  emailtypes.TemplateStore
 	wg                  sync.WaitGroup
 	stopc               chan struct{}
 	notificationManager nfmanager.NotificationManager
@@ -198,6 +205,12 @@ func New(ctx context.Context, logger *slog.Logger, registry prometheus.Registere
 
 	server.pipelineBuilder = notify.NewPipelineBuilder(signozRegisterer, featurecontrol.NoopFlags{})
 	server.dispatcherMetrics = NewDispatcherMetrics(false, signozRegisterer)
+	emailTemplateStore, storeErr := filetemplatestore.NewStore(ctx, srvConfig.EmailTemplatesDirectory, emailtypes.Templates, server.logger)
+	if storeErr != nil {
+		server.logger.ErrorContext(ctx, "failed to create alert email template store, using empty store", errors.Attr(storeErr))
+		emailTemplateStore = filetemplatestore.NewEmptyStore()
+	}
+	server.emailTemplateStore = emailTemplateStore
 
 	return server, nil
 }
@@ -234,6 +247,11 @@ func (server *Server) SetConfig(ctx context.Context, alertmanagerConfig *alertma
 
 	server.tmpl.ExternalURL = server.srvConfig.ExternalURL
 
+	// Construct the alert notification processor
+	templater := alertmanagertemplate.New(server.tmpl, server.logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(server.logger)
+	server.processor = alertnotificationprocessor.New(templater, renderer, server.emailTemplateStore, server.logger)
+
 	// Build the routing tree and record which receivers are used.
 	routes := dispatch.NewRoute(config.Route, nil)
 	activeReceivers := make(map[string]struct{})
@@ -250,7 +268,7 @@ func (server *Server) SetConfig(ctx context.Context, alertmanagerConfig *alertma
 			server.logger.InfoContext(ctx, "skipping creation of receiver not referenced by any route", slog.String("receiver", rcv.Name))
 			continue
 		}
-		integrations, err := alertmanagernotify.NewReceiverIntegrations(rcv, server.tmpl, server.logger)
+		integrations, err := alertmanagernotify.NewReceiverIntegrations(rcv, server.tmpl, server.logger, server.processor)
 		if err != nil {
 			return err
 		}
@@ -326,7 +344,7 @@ func (server *Server) SetConfig(ctx context.Context, alertmanagerConfig *alertma
 
 func (server *Server) TestReceiver(ctx context.Context, receiver alertmanagertypes.Receiver) error {
 	testAlert := alertmanagertypes.NewTestAlert(receiver, time.Now(), time.Now())
-	return alertmanagertypes.TestReceiver(ctx, receiver, alertmanagernotify.NewReceiverIntegrations, server.alertmanagerConfig, server.tmpl, server.logger, testAlert.Labels, testAlert)
+	return alertmanagertypes.TestReceiver(ctx, receiver, alertmanagernotify.NewReceiverIntegrations, server.alertmanagerConfig, server.tmpl, server.logger, server.processor, testAlert.Labels, testAlert)
 }
 
 func (server *Server) TestAlert(ctx context.Context, receiversMap map[*alertmanagertypes.PostableAlert][]string, config *alertmanagertypes.NotificationConfig) error {
@@ -409,6 +427,7 @@ func (server *Server) TestAlert(ctx context.Context, receiversMap map[*alertmana
 					server.alertmanagerConfig,
 					server.tmpl,
 					server.logger,
+					server.processor,
 					group.groupLabels,
 					group.alerts...,
 				)

pkg/alertmanager/alertnotificationprocessor/alertnotificationprocessor.go

@@ -0,0 +1,106 @@
+package alertnotificationprocessor
+
+import (
+	"bytes"
+	"context"
+	htmltemplate "html/template"
+	"log/slog"
+
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/emailtypes"
+	"github.com/prometheus/alertmanager/types"
+)
+
+type alertNotificationProcessor struct {
+	templater     alertmanagertemplate.AlertManagerTemplater
+	renderer      markdownrenderer.MarkdownRenderer
+	logger        *slog.Logger
+	templateStore emailtypes.TemplateStore
+}
+
+func New(templater alertmanagertemplate.AlertManagerTemplater, renderer markdownrenderer.MarkdownRenderer, templateStore emailtypes.TemplateStore, logger *slog.Logger) alertmanagertypes.NotificationProcessor {
+	return &alertNotificationProcessor{
+		templater:     templater,
+		renderer:      renderer,
+		logger:        logger,
+		templateStore: templateStore,
+	}
+}
+
+// emailNotificationTemplateData is the data passed to the email HTML layout template.
+// It embeds NotificationTemplateData so all its fields are directly accessible in the template.
+type emailNotificationTemplateData struct {
+	alertmanagertemplate.NotificationTemplateData
+	Title  string
+	Bodies []htmltemplate.HTML
+}
+
+func (p *alertNotificationProcessor) ProcessAlertNotification(ctx context.Context, input alertmanagertypes.NotificationProcessorInput, alerts []*types.Alert, rendererFormat markdownrenderer.OutputFormat) (*alertmanagertypes.NotificationProcessorResult, error) {
+	// delegate to templater
+	expanded, err := p.templater.ProcessTemplates(ctx, alertmanagertemplate.TemplateInput{
+		TitleTemplate:        input.TitleTemplate,
+		BodyTemplate:         input.BodyTemplate,
+		DefaultTitleTemplate: input.DefaultTitleTemplate,
+		DefaultBodyTemplate:  input.DefaultBodyTemplate,
+	}, alerts)
+	if err != nil {
+		return nil, err
+	}
+
+	// apply rendering to body based on the format
+	var renderedBodies []string
+	if expanded.IsDefaultTemplatedBody {
+		// default templates already produce format-appropriate output
+		renderedBodies = expanded.Body
+	} else {
+		// render each body string using the renderer
+		for _, body := range expanded.Body {
+			rendered, err := p.renderer.Render(ctx, body, rendererFormat)
+			if err != nil {
+				return nil, err
+			}
+			renderedBodies = append(renderedBodies, rendered)
+		}
+	}
+
+	return &alertmanagertypes.NotificationProcessorResult{
+		Title:                  expanded.Title,
+		Body:                   renderedBodies,
+		IsDefaultTemplatedBody: expanded.IsDefaultTemplatedBody,
+		MissingVars:            expanded.MissingVars,
+	}, nil
+}
+
+func (p *alertNotificationProcessor) RenderEmailNotification(
+	ctx context.Context,
+	templateName emailtypes.TemplateName,
+	result *alertmanagertypes.NotificationProcessorResult,
+	alerts []*types.Alert,
+) (string, error) {
+	layoutTmpl, err := p.templateStore.Get(ctx, templateName)
+	if err != nil {
+		return "", err
+	}
+
+	ntd := p.templater.BuildNotificationTemplateData(ctx, alerts)
+
+	bodies := make([]htmltemplate.HTML, 0, len(result.Body))
+	for _, b := range result.Body {
+		bodies = append(bodies, htmltemplate.HTML(b))
+	}
+
+	data := emailNotificationTemplateData{
+		NotificationTemplateData: *ntd,
+		Title:                    result.Title,
+		Bodies:                   bodies,
+	}
+
+	var buf bytes.Buffer
+	if err := layoutTmpl.Execute(&buf, data); err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}

pkg/alertmanager/alertnotificationprocessor/alertnotificationprocessor_test.go

@@ -0,0 +1,343 @@
+package alertnotificationprocessor
+
+import (
+	"context"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"sort"
+	"testing"
+	"time"
+
+	test "github.com/SigNoz/signoz/pkg/alertmanager/alertmanagernotify/alertmanagernotifytest"
+	"github.com/SigNoz/signoz/pkg/alertmanager/alertmanagertemplate"
+	"github.com/SigNoz/signoz/pkg/emailing/templatestore/filetemplatestore"
+	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/alertmanagertypes"
+	"github.com/SigNoz/signoz/pkg/types/emailtypes"
+	"github.com/SigNoz/signoz/pkg/types/ruletypes"
+	"github.com/prometheus/alertmanager/notify"
+	"github.com/prometheus/alertmanager/types"
+	"github.com/prometheus/common/model"
+	"github.com/stretchr/testify/require"
+)
+
+func testSetup(t *testing.T) (alertmanagertypes.NotificationProcessor, context.Context) {
+	t.Helper()
+	tmpl := test.CreateTmpl(t)
+	logger := slog.New(slog.DiscardHandler)
+	templater := alertmanagertemplate.New(tmpl, logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(logger)
+
+	ctx := context.Background()
+	ctx = notify.WithGroupKey(ctx, "test-group")
+	ctx = notify.WithReceiverName(ctx, "slack")
+	ctx = notify.WithGroupLabels(ctx, model.LabelSet{
+		"alertname": "TestAlert",
+		"severity":  "critical",
+	})
+	return New(templater, renderer, filetemplatestore.NewEmptyStore(), logger), ctx
+}
+
+func createAlert(labels, annotations map[string]string, isFiring bool) *types.Alert {
+	ls := model.LabelSet{}
+	for k, v := range labels {
+		ls[model.LabelName(k)] = model.LabelValue(v)
+	}
+	ann := model.LabelSet{}
+	for k, v := range annotations {
+		ann[model.LabelName(k)] = model.LabelValue(v)
+	}
+	startsAt := time.Now()
+	var endsAt time.Time
+	if isFiring {
+		endsAt = startsAt.Add(time.Hour)
+	} else {
+		startsAt = startsAt.Add(-2 * time.Hour)
+		endsAt = startsAt.Add(-time.Hour)
+	}
+	return &types.Alert{Alert: model.Alert{Labels: ls, Annotations: ann, StartsAt: startsAt, EndsAt: endsAt}}
+}
+
+func TestProcessAlertNotification(t *testing.T) {
+	processor, ctx := testSetup(t)
+
+	tests := []struct {
+		name              string
+		alerts            []*types.Alert
+		input             alertmanagertypes.NotificationProcessorInput
+		wantTitle         string
+		wantBody          []string
+		wantIsDefaultBody bool
+		wantMissingVars   []string
+		RendererFormat    markdownrenderer.OutputFormat
+	}{
+		{
+			name: "custom title and body rendered as HTML",
+			alerts: []*types.Alert{
+				createAlert(
+					map[string]string{
+						ruletypes.LabelAlertName:    "HighCPU",
+						ruletypes.LabelSeverityName: "critical",
+						"service":                   "api-server",
+					},
+					map[string]string{"description": "CPU usage exceeded 95%"},
+					true,
+				),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				TitleTemplate: "Alert: $rule_name on $service",
+				BodyTemplate:  "**Service:** $service\n\n**Description:** $description",
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatHTML,
+			wantTitle:         "Alert: HighCPU on api-server",
+			wantBody:          []string{"<p><strong>Service:</strong> api-server</p><p></p><p><strong>Description:</strong> CPU usage exceeded 95%</p><p></p>"},
+			wantIsDefaultBody: false,
+		},
+		{
+			name: "custom title and body rendered as SlackBlockKit",
+			alerts: []*types.Alert{
+				createAlert(
+					map[string]string{
+						ruletypes.LabelAlertName:    "HighMemory",
+						ruletypes.LabelSeverityName: "warning",
+					},
+					map[string]string{"description": "Memory usage high"},
+					true,
+				),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				TitleTemplate: "$rule_name - $severity",
+				BodyTemplate:  "Memory alert: $description",
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatSlackBlockKit,
+			wantTitle:         "HighMemory - warning",
+			wantBody:          []string{`[{"type":"section","text":{"type":"mrkdwn","text":"Memory alert: Memory usage high"}}]`},
+			wantIsDefaultBody: false,
+		},
+		{
+			name: "custom title and body with Noop format passes through as-is",
+			alerts: []*types.Alert{
+				createAlert(
+					map[string]string{
+						ruletypes.LabelAlertName:    "DiskFull",
+						ruletypes.LabelSeverityName: "critical",
+						"host":                      "db-01",
+					},
+					nil,
+					true,
+				),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				TitleTemplate: "$rule_name on $host",
+				BodyTemplate:  "**Host:** $labels.host is full",
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatNoop,
+			wantTitle:         "DiskFull on db-01",
+			wantBody:          []string{"**Host:** db-01 is full"},
+			wantIsDefaultBody: false,
+		},
+		{
+			name: "default fallback when custom templates are empty",
+			alerts: []*types.Alert{
+				createAlert(
+					map[string]string{
+						ruletypes.LabelAlertName:    "TestAlert",
+						ruletypes.LabelSeverityName: "critical",
+					},
+					map[string]string{"description": "Something broke"},
+					true,
+				),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				DefaultTitleTemplate: `{{ .CommonLabels.alertname }} ({{ .Status | toUpper }})`,
+				DefaultBodyTemplate:  `{{ range .Alerts }}{{ .Annotations.description }}{{ end }}`,
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatHTML,
+			wantTitle:         "TestAlert (FIRING)",
+			wantBody:          []string{"Something broke"},
+			wantIsDefaultBody: true,
+		},
+		{
+			name: "missing vars pass through to result",
+			alerts: []*types.Alert{
+				createAlert(
+					map[string]string{ruletypes.LabelAlertName: "TestAlert"},
+					nil,
+					true,
+				),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				TitleTemplate: "[$environment] $rule_name",
+				BodyTemplate:  "See runbook: $runbook_url",
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatNoop,
+			wantTitle:         "[<no value>] TestAlert",
+			wantBody:          []string{"See runbook: <no value>"},
+			wantIsDefaultBody: false,
+			wantMissingVars:   []string{"environment", "runbook_url"},
+		},
+		{
+			name: "slack mrkdwn renders bold and italic correctly along with missing variables",
+			alerts: []*types.Alert{
+				createAlert(
+					map[string]string{
+						ruletypes.LabelAlertName:    "HighCPU",
+						ruletypes.LabelSeverityName: "critical",
+						"service":                   "api-server",
+					},
+					map[string]string{"description": "CPU usage exceeded 95%"},
+					true,
+				),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				TitleTemplate: "Alert: $rule_name",
+				BodyTemplate:  "**Service:** $service\n\n*Description:* $description $http_request_method",
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatSlackMrkdwn,
+			wantTitle:         "Alert: HighCPU",
+			wantBody:          []string{"*Service:* api-server\n\n_Description:_ CPU usage exceeded 95% <no value>\n\n"},
+			wantMissingVars:   []string{"http_request_method"},
+			wantIsDefaultBody: false,
+		},
+		{
+			name: "slack mrkdwn with multiple alerts produces per-alert bodies",
+			alerts: []*types.Alert{
+				createAlert(
+					map[string]string{ruletypes.LabelAlertName: "SvcDown", "service": "auth"},
+					map[string]string{"description": "Auth service **down**"},
+					true,
+				),
+				createAlert(
+					map[string]string{ruletypes.LabelAlertName: "SvcDown", "service": "payments"},
+					map[string]string{"description": "Payments service **degraded**"},
+					false,
+				),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				TitleTemplate: "$rule_name: $total_firing firing, $total_resolved resolved",
+				BodyTemplate:  "**$service** ($status): $description",
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatSlackMrkdwn,
+			wantTitle:         "SvcDown: 1 firing, 1 resolved",
+			wantBody:          []string{"*auth* (firing): Auth service *down*\n\n", "*payments* (resolved): Payments service *degraded*\n\n"},
+			wantIsDefaultBody: false,
+		},
+		{
+			name: "slack mrkdwn skips rendering for default templates",
+			alerts: []*types.Alert{
+				createAlert(
+					map[string]string{
+						ruletypes.LabelAlertName:    "TestAlert",
+						ruletypes.LabelSeverityName: "critical",
+					},
+					map[string]string{"description": "Something broke"},
+					true,
+				),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				DefaultTitleTemplate: `{{ .CommonLabels.alertname }} ({{ .Status | toUpper }})`,
+				DefaultBodyTemplate:  `{{ range .Alerts }}**Bold** *italic* ~~strike~~ {{ .Annotations.description }}{{ end }}`,
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatSlackMrkdwn,
+			wantTitle:         "TestAlert (FIRING)",
+			wantBody:          []string{"**Bold** *italic* ~~strike~~ Something broke"},
+			wantIsDefaultBody: true,
+		},
+		{
+			name: "multiple alerts produce one body entry per alert",
+			alerts: []*types.Alert{
+				createAlert(map[string]string{ruletypes.LabelAlertName: "PodCrash", "pod": "worker-1"}, nil, true),
+				createAlert(map[string]string{ruletypes.LabelAlertName: "PodCrash", "pod": "worker-2"}, nil, true),
+				createAlert(map[string]string{ruletypes.LabelAlertName: "PodCrash", "pod": "worker-3"}, nil, false),
+			},
+			input: alertmanagertypes.NotificationProcessorInput{
+				TitleTemplate: "$rule_name: $total_firing firing",
+				BodyTemplate:  "$labels.pod ($status)",
+			},
+			RendererFormat:    markdownrenderer.MarkdownFormatNoop,
+			wantTitle:         "PodCrash: 2 firing",
+			wantBody:          []string{"worker-1 (firing)", "worker-2 (firing)", "worker-3 (resolved)"},
+			wantIsDefaultBody: false,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result, err := processor.ProcessAlertNotification(ctx, tc.input, tc.alerts, tc.RendererFormat)
+			require.NoError(t, err)
+
+			require.Equal(t, tc.wantTitle, result.Title)
+			require.Equal(t, tc.wantBody, result.Body)
+			require.Equal(t, tc.wantIsDefaultBody, result.IsDefaultTemplatedBody)
+
+			if len(tc.wantMissingVars) == 0 {
+				require.Empty(t, result.MissingVars)
+			} else {
+				sort.Strings(tc.wantMissingVars)
+				require.Equal(t, tc.wantMissingVars, result.MissingVars)
+			}
+		})
+	}
+}
+
+func TestRenderEmailNotification_TemplateNotFound(t *testing.T) {
+	processor, ctx := testSetup(t)
+
+	result := &alertmanagertypes.NotificationProcessorResult{
+		Title: "Test Alert",
+		Body:  []string{"alert body"},
+	}
+	alerts := []*types.Alert{
+		createAlert(map[string]string{ruletypes.LabelAlertName: "TestAlert"}, nil, true),
+	}
+
+	_, err := processor.RenderEmailNotification(ctx, emailtypes.TemplateNameAlertEmailNotification, result, alerts)
+	require.Error(t, err)
+	require.True(t, errors.Ast(err, errors.TypeNotFound))
+}
+
+func TestRenderEmailNotification_RendersTemplate(t *testing.T) {
+	// Create a temp dir with a test template
+	tmpDir := t.TempDir()
+	tmplContent := `<!DOCTYPE html><html><body><h1>{{.Title}}</h1><p>Status: {{.Status}}</p><p>Firing: {{.TotalFiring}}</p>{{range .Bodies}}<div>{{.}}</div>{{end}}{{range .Alerts}}<p>{{.AlertName}}</p>{{end}}</body></html>`
+	err := os.WriteFile(filepath.Join(tmpDir, "alert_email_notification.gotmpl"), []byte(tmplContent), 0644)
+	require.NoError(t, err)
+
+	tmpl := test.CreateTmpl(t)
+	logger := slog.New(slog.DiscardHandler)
+	templater := alertmanagertemplate.New(tmpl, logger)
+	renderer := markdownrenderer.NewMarkdownRenderer(logger)
+	store, err := filetemplatestore.NewStore(context.Background(), tmpDir, emailtypes.Templates, logger)
+	require.NoError(t, err)
+
+	ctx := context.Background()
+	ctx = notify.WithGroupKey(ctx, "test-group")
+	ctx = notify.WithReceiverName(ctx, "email")
+	ctx = notify.WithGroupLabels(ctx, model.LabelSet{
+		"alertname": "HighCPU",
+		"severity":  "critical",
+	})
+
+	processor := New(templater, renderer, store, logger)
+
+	result := &alertmanagertypes.NotificationProcessorResult{
+		Title:                  "HighCPU Alert",
+		Body:                   []string{"<strong>CPU is high</strong>", "<strong>CPU is low</strong>"},
+		IsDefaultTemplatedBody: false,
+	}
+	alerts := []*types.Alert{
+		createAlert(
+			map[string]string{ruletypes.LabelAlertName: "HighCPU", ruletypes.LabelSeverityName: "critical"},
+			nil,
+			true,
+		),
+	}
+
+	html, err := processor.RenderEmailNotification(ctx, emailtypes.TemplateNameAlertEmailNotification, result, alerts)
+	require.NoError(t, err)
+	require.NotEmpty(t, html)
+	// the html template should be filled with go text templating
+	require.Equal(t, "<!DOCTYPE html><html><body><h1>HighCPU Alert</h1><p>Status: firing</p><p>Firing: 1</p><div><strong>CPU is high</strong></div><div><strong>CPU is low</strong></div><p>HighCPU</p></body></html>", html)
+}

pkg/query-service/rules/prom_rule.go

@@ -211,8 +211,23 @@ func (r *PromRule) Eval(ctx context.Context, ts time.Time) (int, error) {
 
 		annotations := make(ruletypes.Labels, 0, len(r.annotations.Map()))
 		for name, value := range r.annotations.Map() {
+			// no need to expand custom templating annotations — they get expanded in the notifier layer
+			if ruletypes.IsCustomTemplatingAnnotation(name) {
+				annotations = append(annotations, ruletypes.Label{Name: name, Value: value})
+				continue
+			}
 			annotations = append(annotations, ruletypes.Label{Name: name, Value: expand(value)})
 		}
+		// Add values to be used in notifier layer for notification templates
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationValue, Value: valueFormatter.Format(result.V, r.Unit())})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationThresholdValue, Value: threshold})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationCompareOp, Value: result.CompareOperator.Literal()})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationMatchType, Value: result.MatchType.Literal()})
+
+		if result.IsRecovering {
+			lb.Set(ruletypes.LabelIsRecovering, "true")
+		}
+
 		if result.IsMissing {
 			lb.Set(ruletypes.AlertNameLabel, "[No data] "+r.Name())
 			lb.Set(ruletypes.NoDataLabel, "true")

pkg/query-service/rules/threshold_rule.go

@@ -337,8 +337,23 @@ func (r *ThresholdRule) Eval(ctx context.Context, ts time.Time) (int, error) {
 
 		annotations := make(ruletypes.Labels, 0, len(r.annotations.Map()))
 		for name, value := range r.annotations.Map() {
+			// no need to expand custom templating annotations — they get expanded in the notifier layer
+			if ruletypes.IsCustomTemplatingAnnotation(name) {
+				annotations = append(annotations, ruletypes.Label{Name: name, Value: value})
+				continue
+			}
 			annotations = append(annotations, ruletypes.Label{Name: name, Value: expand(value)})
 		}
+		// Add values to be used in notifier layer for notification templates
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationValue, Value: value})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationThresholdValue, Value: threshold})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationCompareOp, Value: smpl.CompareOperator.Literal()})
+		annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationMatchType, Value: smpl.MatchType.Literal()})
+
+		if smpl.IsRecovering {
+			lb.Set(ruletypes.LabelIsRecovering, "true")
+		}
+
 		if smpl.IsMissing {
 			lb.Set(ruletypes.AlertNameLabel, "[No data] "+r.Name())
 			lb.Set(ruletypes.NoDataLabel, "true")
@@ -352,13 +367,13 @@ func (r *ThresholdRule) Eval(ctx context.Context, ts time.Time) (int, error) {
 			link := r.prepareLinksToTraces(ctx, ts, smpl.Metric)
 			if link != "" && r.hostFromSource() != "" {
 				r.logger.InfoContext(ctx, "adding traces link to annotations", slog.String("annotation.link", fmt.Sprintf("%s/traces-explorer?%s", r.hostFromSource(), link)))
-				annotations = append(annotations, ruletypes.Label{Name: "related_traces", Value: fmt.Sprintf("%s/traces-explorer?%s", r.hostFromSource(), link)})
+				annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationRelatedTraces, Value: fmt.Sprintf("%s/traces-explorer?%s", r.hostFromSource(), link)})
 			}
 		case ruletypes.AlertTypeLogs:
 			link := r.prepareLinksToLogs(ctx, ts, smpl.Metric)
 			if link != "" && r.hostFromSource() != "" {
 				r.logger.InfoContext(ctx, "adding logs link to annotations", slog.String("annotation.link", fmt.Sprintf("%s/logs/logs-explorer?%s", r.hostFromSource(), link)))
-				annotations = append(annotations, ruletypes.Label{Name: "related_logs", Value: fmt.Sprintf("%s/logs/logs-explorer?%s", r.hostFromSource(), link)})
+				annotations = append(annotations, ruletypes.Label{Name: ruletypes.AnnotationRelatedLogs, Value: fmt.Sprintf("%s/logs/logs-explorer?%s", r.hostFromSource(), link)})
 			}
 		}
 

pkg/types/alertmanagertypes/processor.go

@@ -0,0 +1,47 @@
+package alertmanagertypes
+
+import (
+	"context"
+
+	"github.com/SigNoz/signoz/pkg/templating/markdownrenderer"
+	"github.com/SigNoz/signoz/pkg/types/emailtypes"
+	"github.com/prometheus/alertmanager/types"
+)
+
+// NotificationProcessor orchestrates template expansion and markdown rendering.
+type NotificationProcessor interface {
+	ProcessAlertNotification(ctx context.Context, input NotificationProcessorInput, alerts []*types.Alert, rendererFormat markdownrenderer.OutputFormat) (*NotificationProcessorResult, error)
+	// RenderEmailNotification renders the given processor result into final HTML using
+	// the named layout template from the file template store.
+	// Returns an error if the template is not found.
+	RenderEmailNotification(ctx context.Context, templateName emailtypes.TemplateName, result *NotificationProcessorResult, alerts []*types.Alert) (string, error)
+}
+
+// NotificationProcessorInput carries the templates and rendering format for a notification.
+type NotificationProcessorInput struct {
+	TitleTemplate        string
+	BodyTemplate         string
+	DefaultTitleTemplate string
+	DefaultBodyTemplate  string
+}
+
+// NotificationProcessorResult has the final expanded and rendered notification content.
+type NotificationProcessorResult struct {
+	Title string
+	// Body contains per-alert rendered body strings.
+	Body []string
+	// IsDefaultTemplatedBody indicates the body came from default
+	// templates rather than custom annotation templates.
+	// Notifiers use this to decide presentation (e.g., Slack: single
+	// attachment vs. multiple BlockKit attachments).
+	IsDefaultTemplatedBody bool
+	// MissingVars is the union of unknown $variables found during
+	// custom template expansion.
+	MissingVars []string
+}
+
+// IsCustomTemplated returns true if the body came from custom annotation templates
+// rather than default templates.
+func (npr NotificationProcessorResult) IsCustomTemplated() bool {
+	return !npr.IsDefaultTemplatedBody
+}

pkg/types/alertmanagertypes/receiver.go

@@ -4,10 +4,11 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"github.com/prometheus/common/model"
 	"log/slog"
 	"time"
 
+	"github.com/prometheus/common/model"
+
 	"github.com/SigNoz/signoz/pkg/errors"
 	"github.com/prometheus/alertmanager/notify"
 	"github.com/prometheus/alertmanager/template"
@@ -19,7 +20,7 @@ import (
 type (
 	// Receiver is the type for the receiver configuration.
 	Receiver                 = config.Receiver
-	ReceiverIntegrationsFunc = func(nc Receiver, tmpl *template.Template, logger *slog.Logger) ([]notify.Integration, error)
+	ReceiverIntegrationsFunc = func(nc Receiver, tmpl *template.Template, logger *slog.Logger, processor NotificationProcessor) ([]notify.Integration, error)
 )
 
 // Creates a new receiver from a string. The input is initialized with the default values from the upstream alertmanager.
@@ -50,7 +51,7 @@ func NewReceiver(input string) (Receiver, error) {
 	return receiverWithDefaults, nil
 }
 
-func TestReceiver(ctx context.Context, receiver Receiver, receiverIntegrationsFunc ReceiverIntegrationsFunc, config *Config, tmpl *template.Template, logger *slog.Logger, lSet model.LabelSet, alert ...*Alert) error {
+func TestReceiver(ctx context.Context, receiver Receiver, receiverIntegrationsFunc ReceiverIntegrationsFunc, config *Config, tmpl *template.Template, logger *slog.Logger, processor NotificationProcessor, lSet model.LabelSet, alert ...*Alert) error {
 	ctx = notify.WithGroupKey(ctx, fmt.Sprintf("%s-%s-%d", receiver.Name, lSet.Fingerprint(), time.Now().Unix()))
 	ctx = notify.WithGroupLabels(ctx, lSet)
 	ctx = notify.WithReceiverName(ctx, receiver.Name)
@@ -72,7 +73,7 @@ func TestReceiver(ctx context.Context, receiver Receiver, receiverIntegrationsFu
 		return err
 	}
 
-	integrations, err := receiverIntegrationsFunc(receiver, tmpl, logger)
+	integrations, err := receiverIntegrationsFunc(receiver, tmpl, logger, processor)
 	if err != nil {
 		return err
 	}

pkg/types/alertmanagertypes/template.go

@@ -11,6 +11,11 @@ import (
 	alertmanagertemplate "github.com/prometheus/alertmanager/template"
 )
 
+const (
+	// NoOpTemplateString is a placeholder template string that is used when no templating is required.
+	NoOpTemplateString = "NO_OP"
+)
+
 func AdditionalFuncMap() tmpltext.FuncMap {
 	return tmpltext.FuncMap{
 		// urlescape escapes the string for use in a URL query parameter.

pkg/types/emailtypes/template.go

@@ -12,13 +12,14 @@ import (
 var (
 	// Templates is a list of all the templates that are supported by the emailing service.
 	// This list should be updated whenever a new template is added.
-	Templates = []TemplateName{TemplateNameInvitationEmail, TemplateNameResetPassword}
+	Templates = []TemplateName{TemplateNameInvitationEmail, TemplateNameResetPassword, TemplateNameAlertEmailNotification}
 )
 
 var (
 	TemplateNameInvitationEmail = TemplateName{valuer.NewString("invitation")}
 	TemplateNameResetPassword   = TemplateName{valuer.NewString("reset_password")}
-	TemplateNameAPIKeyEvent     = TemplateName{valuer.NewString("api_key_event")}
+	TemplateNameAPIKeyEvent              = TemplateName{valuer.NewString("api_key_event")}
+	TemplateNameAlertEmailNotification = TemplateName{valuer.NewString("alert_email_notification")}
 )
 
 type TemplateName struct{ valuer.String }
@@ -31,6 +32,8 @@ func NewTemplateName(name string) (TemplateName, error) {
 		return TemplateNameResetPassword, nil
 	case TemplateNameAPIKeyEvent.StringValue():
 		return TemplateNameAPIKeyEvent, nil
+	case TemplateNameAlertEmailNotification.StringValue():
+		return TemplateNameAlertEmailNotification, nil
 	default:
 		return TemplateName{}, errors.Newf(errors.TypeInvalidInput, errors.CodeInvalidInput, "invalid template name: %s", name)
 	}

pkg/types/ruletypes/compare.go

@@ -77,6 +77,28 @@ func (c CompareOperator) Normalize() CompareOperator {
 	}
 }
 
+// Literal returns the canonical literal (string) form of the operator.
+func (c CompareOperator) Literal() string {
+	switch c.Normalize() {
+	case ValueIsAbove:
+		return ValueIsAboveLiteral.StringValue()
+	case ValueIsBelow:
+		return ValueIsBelowLiteral.StringValue()
+	case ValueIsEq:
+		return ValueIsEqLiteral.StringValue()
+	case ValueIsNotEq:
+		return ValueIsNotEqLiteral.StringValue()
+	case ValueAboveOrEq:
+		return ValueAboveOrEqLiteral.StringValue()
+	case ValueBelowOrEq:
+		return ValueBelowOrEqLiteral.StringValue()
+	case ValueOutsideBounds:
+		return ValueOutsideBoundsLiteral.StringValue()
+	default:
+		return c.StringValue()
+	}
+}
+
 func (c CompareOperator) Validate() error {
 	switch c {
 	case ValueIsAbove,

pkg/types/ruletypes/match.go

@@ -56,6 +56,24 @@ func (m MatchType) Normalize() MatchType {
 	}
 }
 
+// Literal returns the canonical literal (string) form of the match type.
+func (m MatchType) Literal() string {
+	switch m.Normalize() {
+	case AtleastOnce:
+		return AtleastOnceLiteral.StringValue()
+	case AllTheTimes:
+		return AllTheTimesLiteral.StringValue()
+	case OnAverage:
+		return OnAverageLiteral.StringValue()
+	case InTotal:
+		return InTotalLiteral.StringValue()
+	case Last:
+		return LastLiteral.StringValue()
+	default:
+		return m.StringValue()
+	}
+}
+
 func (m MatchType) Validate() error {
 	switch m {
 	case

pkg/types/ruletypes/result_types.go

@@ -24,6 +24,10 @@ type Sample struct {
 	RecoveryTarget *float64
 
 	TargetUnit string
+
+	// CompareOperator and MatchType carry the threshold evaluation context
+	CompareOperator CompareOperator
+	MatchType       MatchType
 }
 
 func (s Sample) String() string {

pkg/types/ruletypes/templating.go

@@ -0,0 +1,17 @@
+package ruletypes
+
+var CustomTemplatingAnnotations = []string{
+	AnnotationTitleTemplate,
+	AnnotationBodyTemplate,
+}
+
+// IsCustomTemplatingAnnotation checks if the given annotation is a custom templating annotation
+// in order to avoid expanding them in the rule manager layer.
+func IsCustomTemplatingAnnotation(name string) bool {
+	for _, annotation := range CustomTemplatingAnnotations {
+		if annotation == name {
+			return true
+		}
+	}
+	return false
+}

pkg/types/ruletypes/threshold.go

@@ -143,6 +143,8 @@ func (r BasicRuleThresholds) Eval(s *qbtypes.TimeSeries, unit string, evalData E
 				smpl.RecoveryTarget = threshold.RecoveryTarget
 			}
 			smpl.TargetUnit = threshold.TargetUnit
+			smpl.CompareOperator = threshold.CompareOperator
+			smpl.MatchType = threshold.MatchType
 			resultVector = append(resultVector, smpl)
 			continue
 		} else if evalData.SendUnmatched {
@@ -152,10 +154,12 @@ func (r BasicRuleThresholds) Eval(s *qbtypes.TimeSeries, unit string, evalData E
 			}
 			// prepare the sample with the first point of the series
 			smpl := Sample{
-				Point:      Point{T: series.Values[0].Timestamp, V: series.Values[0].Value},
-				Metric:     PrepareSampleLabelsForRule(series.Labels, threshold.Name),
-				Target:     *threshold.TargetValue,
-				TargetUnit: threshold.TargetUnit,
+				Point:           Point{T: series.Values[0].Timestamp, V: series.Values[0].Value},
+				Metric:          PrepareSampleLabelsForRule(series.Labels, threshold.Name),
+				Target:          *threshold.TargetValue,
+				TargetUnit:      threshold.TargetUnit,
+				CompareOperator: threshold.CompareOperator,
+				MatchType:       threshold.MatchType,
 			}
 			if threshold.RecoveryTarget != nil {
 				smpl.RecoveryTarget = threshold.RecoveryTarget
@@ -177,6 +181,8 @@ func (r BasicRuleThresholds) Eval(s *qbtypes.TimeSeries, unit string, evalData E
 				smpl.Target = *threshold.TargetValue
 				smpl.RecoveryTarget = threshold.RecoveryTarget
 				smpl.TargetUnit = threshold.TargetUnit
+				smpl.CompareOperator = threshold.CompareOperator
+				smpl.MatchType = threshold.MatchType
 				// IsRecovering to notify that metrics is in recovery stage
 				smpl.IsRecovering = true
 				resultVector = append(resultVector, smpl)

templates/email/alert_email_notification.gotmpl

@@ -0,0 +1,120 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge">
+  <title>{{.Title}}</title>
+  <style>
+    code {
+      background: #f0f0f0;
+      padding: 2px 6px;
+      border-radius: 3px;
+      font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
+      font-size: 13px;
+    }
+    pre {
+      background: #f0f0f0;
+      padding: 12px 16px;
+      border-radius: 6px;
+      font-size: 13px;
+      overflow-x: auto;
+      white-space: pre;
+    }
+    pre code {
+      background: none;
+      padding: 0;
+      border-radius: 0;
+      font-size: inherit;
+    }
+    table:not([role="presentation"]) {
+      width: 100%;
+      border-collapse: collapse;
+      font-size: 14px;
+    }
+    table:not([role="presentation"]) th {
+      font-weight: 600;
+      text-align: left;
+      padding: 8px 12px;
+      border-bottom: 2px solid #d0d0d0;
+    }
+    table:not([role="presentation"]) td {
+      padding: 8px 12px;
+      border-bottom: 1px solid #e8e8e8;
+    }
+    table:not([role="presentation"]) tr:last-child td {
+      border-bottom: none;
+    }
+  </style>
+</head>
+
+<body style="margin:0;padding:0;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,'Helvetica Neue',Arial,sans-serif;line-height:1.6;color:#333;background:#fff">
+  <table role="presentation" width="100%" cellspacing="0" cellpadding="0" border="0" style="background:#fff">
+    <tr>
+      <td align="center" style="padding:0">
+        <table role="presentation" width="600" cellspacing="0" cellpadding="0" border="0" style="max-width:600px;width:100%;border:1px solid #e2e2e2;border-radius:12px;overflow:hidden">
+
+          <tr>
+            <td align="center" style="padding:20px 20px 12px">
+              <h2 style="margin:0 0 8px;font-size:20px;color:#333">{{.Title}}</h2>
+              <p style="margin:0;font-size:14px;color:#666">
+                Status: <strong>{{.Status}}</strong>
+                {{if .TotalFiring}} | Firing: <strong style="color:#e53e3e">{{.TotalFiring}}</strong>{{end}}
+                {{if .TotalResolved}} | Resolved: <strong style="color:#38a169">{{.TotalResolved}}</strong>{{end}}
+              </p>
+            </td>
+          </tr>
+
+          <tr>
+            <td style="padding:0 20px">
+              <table role="presentation" width="100%" cellspacing="0" cellpadding="0" border="0">
+                <tr><td style="border-top:1px solid #e2e2e2;font-size:0;line-height:0" height="1">&nbsp;</td></tr>
+              </table>
+            </td>
+          </tr>
+
+          {{range .Bodies}}
+          <tr>
+            <td style="padding:8px 20px">
+              <table role="presentation" width="100%" cellspacing="0" cellpadding="0" border="0">
+                <tr>
+                  <td style="padding:16px;background:#fafafa;border:1px solid #e8e8e8;border-radius:6px">
+                    {{.}}
+                  </td>
+                </tr>
+              </table>
+            </td>
+          </tr>
+          {{end}}
+
+          {{if .ExternalURL}}
+          <tr>
+            <td style="padding:16px 20px">
+              <table role="presentation" width="100%" cellspacing="0" cellpadding="0" border="0">
+                <tr>
+                  <td align="center">
+                    <a href="{{.ExternalURL}}" target="_blank" style="display:inline-block;padding:12px 32px;font-size:14px;font-weight:600;color:#fff;background:#4E74F8;text-decoration:none;border-radius:4px">
+                      View in SigNoz
+                    </a>
+                  </td>
+                </tr>
+              </table>
+            </td>
+          </tr>
+          {{end}}
+
+          <tr>
+            <td align="center" style="padding:8px 16px 16px">
+              <p style="margin:0;font-size:12px;color:#999;line-height:1.5">
+                Sent by SigNoz AlertManager
+              </p>
+            </td>
+          </tr>
+        </table>
+      </td>
+    </tr>
+  </table>
+</body>
+
+</html>

tests/integration/conftest.py

@@ -23,6 +23,7 @@ pytest_plugins = [
     "fixtures.notification_channel",
     "fixtures.alerts",
     "fixtures.cloudintegrations",
+    "fixtures.maildev",
 ]
 
 

tests/integration/fixtures/alertutils.py

@@ -9,10 +9,35 @@ import requests
 
 from fixtures import types
 from fixtures.logger import setup_logger
+from fixtures.maildev import verify_email_received
+from urllib.parse import urlparse
 
 logger = setup_logger(__name__)
 
 
+def _is_json_subset(subset, superset) -> bool:
+    """Check if subset is contained within superset recursively.
+    - For dicts: all keys in subset must exist in superset with matching values
+    - For lists: all items in subset must be present in superset
+    - For scalars: exact equality
+    """
+    if isinstance(subset, dict):
+        if not isinstance(superset, dict):
+            return False
+        return all(
+            key in superset and _is_json_subset(value, superset[key])
+            for key, value in subset.items()
+        )
+    if isinstance(subset, list):
+        if not isinstance(superset, list):
+            return False
+        return all(
+            any(_is_json_subset(sub_item, sup_item) for sup_item in superset)
+            for sub_item in subset
+        )
+    return subset == superset
+
+
 def collect_webhook_firing_alerts(
     webhook_test_container: types.TestContainerDocker, notification_channel_name: str
 ) -> List[types.FiringAlert]:
@@ -73,6 +98,88 @@ def _verify_alerts_labels(
 
     return (fired_count, missing_alerts)
 
+def verify_webhook_notification_expectation(
+    notification_channel: types.TestContainerDocker,
+    validation_data: dict,
+) -> bool:
+    """Check if wiremock received a request at the given path
+    whose JSON body is a superset of the expected json_body."""
+    path = validation_data["path"]
+    json_body = validation_data["json_body"]
+
+    url = notification_channel.host_configs["8080"].get("__admin/requests/find")
+    res = requests.post(url, json={"method": "POST", "url": path}, timeout=5)
+    assert res.status_code == HTTPStatus.OK, (
+        f"Failed to find requests for path {path}, "
+        f"status code: {res.status_code}, response: {res.text}"
+    )
+
+    for req in res.json()["requests"]:
+        body = json.loads(base64.b64decode(req["bodyAsBase64"]).decode("utf-8"))
+        if _is_json_subset(json_body, body):
+            return True
+    return False
+
+
+def _check_notification_validation(
+    validation: types.NotificationValidation,
+    notification_channel: types.TestContainerDocker,
+    maildev: types.TestContainerDocker,
+) -> bool:
+    """Dispatch a single validation check to the appropriate verifier."""
+    if validation.destination_type == "webhook":
+        return verify_webhook_notification_expectation(
+            notification_channel, validation.validation_data
+        )
+    if validation.destination_type == "email":
+        return verify_email_received(maildev, validation.validation_data)
+    raise ValueError(f"Invalid destination type: {validation.destination_type}")
+
+
+def verify_notification_expectation(
+    notification_channel: types.TestContainerDocker,
+    maildev: types.TestContainerDocker,
+    expected_notification: types.AMNotificationExpectation,
+) -> bool:
+    """Poll for expected notifications across webhook and email channels."""
+    time_to_wait = datetime.now() + timedelta(
+        seconds=expected_notification.wait_time_seconds
+    )
+
+    while datetime.now() < time_to_wait:
+        all_found = all(
+            _check_notification_validation(v, notification_channel, maildev)
+            for v in expected_notification.notification_validations
+        )
+
+        if expected_notification.should_notify and all_found:
+            logger.info("All expected notifications found")
+            return True
+
+        time.sleep(1)
+
+    # Timeout reached
+    if not expected_notification.should_notify:
+        # Verify no notifications were received
+        for validation in expected_notification.notification_validations:
+            found = _check_notification_validation(validation, notification_channel, maildev)
+            assert not found, (
+                f"Expected no notification but found one for "
+                f"{validation.destination_type} with data {validation.validation_data}"
+            )
+        logger.info("No notifications found, as expected")
+        return True
+
+    # Expected notifications but didn't get them all — report missing
+    missing = [
+        v for v in expected_notification.notification_validations
+        if not _check_notification_validation(v, notification_channel, maildev)
+    ]
+    assert len(missing) == 0, (
+        f"Expected all notifications to be found but missing: {missing}"
+    )
+    return True
+
 
 def verify_webhook_alert_expectation(
     test_alert_container: types.TestContainerDocker,
@@ -135,6 +242,37 @@ def verify_webhook_alert_expectation(
     return True  # should not reach here
 
 
+def update_channel_config_urls(
+    channel_config: dict,
+    notification_channel: types.TestContainerDocker,
+) -> dict:
+    """
+    Updates the channel config to point to the given wiremock
+    notification_channel container to receive notifications.
+    """
+    config = channel_config.copy()
+
+    url_field_map = {
+        "slack_configs": "api_url",
+        "msteams_configs": "webhook_url",
+        "webhook_configs": "url",
+        "pagerduty_configs": "url",
+        "opsgenie_configs": "api_url",
+    }
+
+    for config_key, url_field in url_field_map.items():
+        if config_key in config:
+            for entry in config[config_key]:
+                if url_field in entry:
+                    original_url = entry[url_field]
+                    path = urlparse(original_url).path
+                    entry[url_field] = notification_channel.container_configs[
+                        "8080"
+                    ].get(path)
+
+    return config
+
+
 def update_rule_channel_name(rule_data: dict, channel_name: str):
     """
     updates the channel name in the thresholds

tests/integration/fixtures/maildev.py

@@ -0,0 +1,136 @@
+from http import HTTPStatus
+import json
+from typing import List
+
+import docker
+import docker.errors
+import pytest
+import requests
+from testcontainers.core.container import DockerContainer, Network
+
+from fixtures import dev, types
+from fixtures.logger import setup_logger
+
+logger = setup_logger(__name__)
+
+
+@pytest.fixture(name="maildev", scope="package")
+def maildev(
+    network: Network, request: pytest.FixtureRequest, pytestconfig: pytest.Config
+) -> types.TestContainerDocker:
+    """
+    Package-scoped fixture for MailDev container.
+    Provides SMTP (port 1025) and HTTP API (port 1080) for email testing.
+    """
+
+    def create() -> types.TestContainerDocker:
+        container = DockerContainer(image="maildev/maildev:2.1.0")
+        container.with_exposed_ports(1025, 1080)
+        container.with_network(network=network)
+        container.start()
+
+        return types.TestContainerDocker(
+            id=container.get_wrapped_container().id,
+            host_configs={
+                "1025": types.TestContainerUrlConfig(
+                    scheme="smtp",
+                    address=container.get_container_host_ip(),
+                    port=container.get_exposed_port(1025),
+                ),
+                "1080": types.TestContainerUrlConfig(
+                    scheme="http",
+                    address=container.get_container_host_ip(),
+                    port=container.get_exposed_port(1080),
+                ),
+            },
+            container_configs={
+                "1025": types.TestContainerUrlConfig(
+                    scheme="smtp",
+                    address=container.get_wrapped_container().name,
+                    port=1025,
+                ),
+                "1080": types.TestContainerUrlConfig(
+                    scheme="http",
+                    address=container.get_wrapped_container().name,
+                    port=1080,
+                ),
+            },
+        )
+
+    def delete(container: types.TestContainerDocker):
+        client = docker.from_env()
+        try:
+            client.containers.get(container_id=container.id).stop()
+            client.containers.get(container_id=container.id).remove(v=True)
+        except docker.errors.NotFound:
+            logger.info(
+                "Skipping removal of MailDev, MailDev(%s) not found. Maybe it was manually removed?",
+                {"id": container.id},
+            )
+
+    def restore(cache: dict) -> types.TestContainerDocker:
+        return types.TestContainerDocker.from_cache(cache)
+
+    return dev.wrap(
+        request,
+        pytestconfig,
+        "maildev",
+        lambda: types.TestContainerDocker(id="", host_configs={}, container_configs={}),
+        create,
+        delete,
+        restore,
+    )
+
+
+def get_all_mails(maildev: types.TestContainerDocker) -> List[dict]:
+    """
+    Fetches all emails from the MailDev HTTP API.
+    Returns list of dicts with keys: subject, html, text.
+    """
+    url = maildev.host_configs["1080"].get("/email")
+    response = requests.get(url, timeout=5)
+    assert response.status_code == HTTPStatus.OK, (
+        f"Failed to fetch emails from MailDev, "
+        f"status code: {response.status_code}, response: {response.text}"
+    )
+    emails = response.json()
+    # logger.debug("Emails: %s", json.dumps(emails, indent=2))
+    return [
+        {
+            "subject": email.get("subject", ""),
+            "html": email.get("html", ""),
+            "text": email.get("text", ""),
+        }
+        for email in emails
+    ]
+
+
+def verify_email_received(
+    maildev: types.TestContainerDocker, filters: dict
+) -> bool:
+    """
+    Checks if any email in MailDev matches all the given filters.
+    Filters are matched with exact equality against the email fields (subject, html, text).
+    Returns True if at least one matching email is found.
+    """
+    emails = get_all_mails(maildev)
+    for email in emails:
+        # logger.debug("Email: %s", json.dumps(email, indent=2))
+        if all(
+            key in email and filter_value == email[key]
+            for key, filter_value in filters.items()
+        ):
+            return True
+    return False
+
+
+def delete_all_mails(maildev: types.TestContainerDocker) -> None:
+    """
+    Deletes all emails from the MailDev inbox.
+    """
+    url = maildev.host_configs["1080"].get("/email/all")
+    response = requests.delete(url, timeout=5)
+    assert response.status_code == HTTPStatus.OK, (
+        f"Failed to delete emails from MailDev, "
+        f"status code: {response.status_code}, response: {response.text}"
+    )

tests/integration/fixtures/notification_channel.py

@@ -70,6 +70,29 @@ def notification_channel(
         restore,
     )
 
+@pytest.fixture(name="create_notification_channel", scope="function")
+def create_notification_channel(
+    signoz: types.SigNoz,
+    create_user_admin: None,  # pylint: disable=unused-argument
+    get_token: Callable[[str, str], str],
+) -> Callable[[dict], str]:
+    admin_token = get_token(USER_ADMIN_EMAIL, USER_ADMIN_PASSWORD)
+
+    def _create_notification_channel(channel_config: dict) -> str:
+        response = requests.post(
+            signoz.self.host_configs["8080"].get("/api/v1/channels"),
+            json=channel_config,
+            headers={"Authorization": f"Bearer {admin_token}"},
+            timeout=5,
+        )
+        assert response.status_code == HTTPStatus.CREATED, (
+            f"Failed to create channel, "
+            f"Response: {response.text} "
+            f"Response status: {response.status_code}"
+        )
+        return response.json()["data"]["id"]
+
+    return _create_notification_channel
 
 @pytest.fixture(name="create_webhook_notification_channel", scope="function")
 def create_webhook_notification_channel(

tests/integration/fixtures/types.py

@@ -203,3 +203,37 @@ class AlertTestCase:
     alert_data: List[AlertData]
     # list of alert expectations for the test case
     alert_expectation: AlertExpectation
+
+@dataclass(frozen=True)
+class NotificationValidation:
+    # destination type of the notification, either webhook or email
+    # slack, msteams, pagerduty, opsgenie, webhook channels send notifications through webhook
+    # email channels send notifications through email
+    destination_type: Literal["webhook", "email"]
+    # validation data for validating the received notification payload
+    validation_data: dict[str, any]
+
+@dataclass(frozen=True)
+class AMNotificationExpectation:
+    # whether we expect any notifications to be fired or not, false when testing downtime scenarios
+    # or don't expect any notifications to be fired in given time period
+    should_notify: bool
+    # seconds to wait for the notifications to be fired, if no
+    # notifications are fired in the expected time, the test will fail
+    wait_time_seconds: int
+    # list of notifications to expect, as a single rule can trigger multiple notifications
+    # spanning across different notifiers
+    notification_validations: List[NotificationValidation]
+
+@dataclass(frozen=True)
+class AlertManagerNotificationTestCase:
+    # name of the test case
+    name: str
+    # path to the rule file in testdata directory
+    rule_path: str
+    # list of alert data that will be inserted into the database for the rule to be triggered
+    alert_data: List[AlertData]
+    # configuration for the notification channel
+    channel_config: dict[str, any]
+    # notification expectations for the test case
+    notification_expectation: AMNotificationExpectation

tests/integration/src/alertmanager/01_notifers.py

@@ -0,0 +1,357 @@
+import json
+import uuid
+from datetime import datetime, timedelta, timezone
+from typing import Callable, List
+
+import pytest
+from wiremock.client import HttpMethods, Mapping, MappingRequest, MappingResponse
+
+from fixtures import types
+from fixtures.alertutils import (
+    update_channel_config_urls,
+    update_rule_channel_name,
+    verify_notification_expectation,
+)
+from fixtures.logger import setup_logger
+from fixtures.utils import get_testdata_file_path
+
+
+"""
+Default notification configs for each of the notifiers
+"""
+
+slack_default_config = {
+    # channel name configured on runtime
+    "slack_configs": [{
+        "api_url": "services/TEAM_ID/BOT_ID/TOKEN_ID", # base_url configured on runtime
+        "title":"[{{ .Status | toUpper }}{{ if eq .Status \"firing\" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}\n {{- if gt (len .CommonLabels) (len .GroupLabels) -}}\n {{\" \"}}(\n {{- with .CommonLabels.Remove .GroupLabels.Names }}\n {{- range $index, $label := .SortedPairs -}}\n {{ if $index }}, {{ end }}\n {{- $label.Name }}=\"{{ $label.Value -}}\"\n {{- end }}\n {{- end -}}\n )\n {{- end }}",
+        "text":"{{ range .Alerts -}}\r\n *Alert:* {{ .Labels.alertname }}{{ if .Labels.severity }} - {{ .Labels.severity }}{{ end }}\r\n\r\n *Summary:* {{ .Annotations.summary }}\r\n *Description:* {{ .Annotations.description }}\r\n *RelatedLogs:* {{ if gt (len .Annotations.related_logs) 0 -}} View in <{{ .Annotations.related_logs }}|logs explorer> {{- end}}\r\n *RelatedTraces:* {{ if gt (len .Annotations.related_traces) 0 -}} View in <{{ .Annotations.related_traces }}|traces explorer> {{- end}}\r\n\r\n *Details:*\r\n {{ range .Labels.SortedPairs -}}\r\n   {{- if ne .Name \"ruleId\" -}}\r\n \u2022 *{{ .Name }}:* {{ .Value }}\r\n   {{ end -}}\r\n {{ end -}}\r\n{{ end }}"
+    }],
+}
+
+# MSTeams default config
+msteams_default_config = {
+    "msteams_configs": [{
+        "webhook_url": "msteams/webhook_url", # base_url configured on runtime
+        "title":"[{{ .Status | toUpper }}{{ if eq .Status \"firing\" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}\n {{- if gt (len .CommonLabels) (len .GroupLabels) -}}\n {{\" \"}}(\n {{- with .CommonLabels.Remove .GroupLabels.Names }}\n {{- range $index, $label := .SortedPairs -}}\n {{ if $index }}, {{ end }}\n {{- $label.Name }}=\"{{ $label.Value -}}\"\n {{- end }}\n {{- end -}}\n )\n {{- end }}",
+        "text":"{{ range .Alerts -}}\r\n *Alert:* {{ .Labels.alertname }}{{ if .Labels.severity }} - {{ .Labels.severity }}{{ end }}\r\n\r\n *Summary:* {{ .Annotations.summary }}\r\n *Description:* {{ .Annotations.description }}\r\n *RelatedLogs:* {{ if gt (len .Annotations.related_logs) 0 -}} View in <{{ .Annotations.related_logs }}|logs explorer> {{- end}}\r\n *RelatedTraces:* {{ if gt (len .Annotations.related_traces) 0 -}} View in <{{ .Annotations.related_traces }}|traces explorer> {{- end}}\r\n\r\n *Details:*\r\n {{ range .Labels.SortedPairs -}}\r\n   {{- if ne .Name \"ruleId\" -}}\r\n \u2022 *{{ .Name }}:* {{ .Value }}\r\n   {{ end -}}\r\n {{ end -}}\r\n{{ end }}"
+    }],
+}
+
+# pagerduty default config
+pagerduty_default_config = {
+    "pagerduty_configs": [{
+        "routing_key":"PagerDutyRoutingKey",
+        "url":"v2/enqueue", # base_url configured on runtime
+        "client":"SigNoz Alert Manager",
+        "client_url":"https://enter-signoz-host-n-port-here/alerts",
+        "description":"[{{ .Status | toUpper }}{{ if eq .Status \"firing\" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}\n\t{{- if gt (len .CommonLabels) (len .GroupLabels) -}}\n\t {{\" \"}}(\n\t {{- with .CommonLabels.Remove .GroupLabels.Names }}\n\t\t{{- range $index, $label := .SortedPairs -}}\n\t\t {{ if $index }}, {{ end }}\n\t\t {{- $label.Name }}=\"{{ $label.Value -}}\"\n\t\t{{- end }}\n\t {{- end -}}\n\t )\n\t{{- end }}",
+        "details":{
+            "firing":"{{ template \"pagerduty.default.instances\" .Alerts.Firing }}",
+            "num_firing":"{{ .Alerts.Firing | len }}",
+            "num_resolved":"{{ .Alerts.Resolved | len }}",
+            "resolved":"{{ template \"pagerduty.default.instances\" .Alerts.Resolved }}"
+        },
+        "source":"SigNoz Alert Manager",
+        "severity":"{{ (index .Alerts 0).Labels.severity }}"
+    }],
+}
+# opsgenie default config
+opsgenie_default_config = {
+   "opsgenie_configs": [
+    {
+      "api_key": "OpsGenieAPIKey",
+      "api_url": "/", # base_url configured on runtime
+      "description": "{{ if gt (len .Alerts.Firing) 0 -}}\r\n\tAlerts Firing:\r\n\t{{ range .Alerts.Firing }}\r\n\t - Message: {{ .Annotations.description }}\r\n\tLabels:\r\n\t{{ range .Labels.SortedPairs -}}\r\n\t\t{{- if ne .Name \"ruleId\" }}   - {{ .Name }} = {{ .Value }}\r\n\t{{ end -}}\r\n\t{{- end }}   Annotations:\r\n\t{{ range .Annotations.SortedPairs }}   - {{ .Name }} = {{ .Value }}\r\n\t{{ end }}   Source: {{ .GeneratorURL }}\r\n\t{{ end }}\r\n{{- end }}\r\n{{ if gt (len .Alerts.Resolved) 0 -}}\r\n\tAlerts Resolved:\r\n\t{{ range .Alerts.Resolved }}\r\n\t - Message: {{ .Annotations.description }}\r\n\tLabels:\r\n\t{{ range .Labels.SortedPairs -}}\r\n\t\t{{- if ne .Name \"ruleId\" }}   - {{ .Name }} = {{ .Value }}\r\n\t{{ end -}}\r\n\t{{- end }}   Annotations:\r\n\t{{ range .Annotations.SortedPairs }}   - {{ .Name }} = {{ .Value }}\r\n\t{{ end }}   Source: {{ .GeneratorURL }}\r\n\t{{ end }}\r\n{{- end }}",
+      "priority": "{{ if eq (index .Alerts 0).Labels.severity \"critical\" }}P1{{ else if eq (index .Alerts 0).Labels.severity \"warning\" }}P2{{ else if eq (index .Alerts 0).Labels.severity \"info\" }}P3{{ else }}P4{{ end }}",
+      "message": "{{ .CommonLabels.alertname }}",
+      "details": {}
+    }
+  ]
+}
+
+# webhook default config
+webhook_default_config = {
+    "webhook_configs": [{
+        "url": "webhook/webhook_url", # base_url configured on runtime
+    }],
+}
+# email default config
+email_default_config = {
+    "email_configs": [{
+        "to": "test@example.com",
+        "html": "<html><body>{{ range .Alerts -}}\r\n *Alert:* {{ .Labels.alertname }}{{ if .Labels.severity }} - {{ .Labels.severity }}{{ end }}\r\n\r\n *Summary:* {{ .Annotations.summary }}\r\n *Description:* {{ .Annotations.description }}\r\n *RelatedLogs:* {{ if gt (len .Annotations.related_logs) 0 -}} View in <{{ .Annotations.related_logs }}|logs explorer> {{- end}}\r\n *RelatedTraces:* {{ if gt (len .Annotations.related_traces) 0 -}} View in <{{ .Annotations.related_traces }}|traces explorer> {{- end}}\r\n\r\n *Details:*\r\n {{ range .Labels.SortedPairs -}}\r\n   {{- if ne .Name \"ruleId\" -}}\r\n \u2022 *{{ .Name }}:* {{ .Value }}\r\n   {{ end -}}\r\n {{ end -}}\r\n{{ end }}</body></html>",
+        "headers": {
+            "Subject": "[{{ .Status | toUpper }}{{ if eq .Status \"firing\" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}\n {{- if gt (len .CommonLabels) (len .GroupLabels) -}}\n {{\" \"}}(\n {{- with .CommonLabels.Remove .GroupLabels.Names }}\n {{- range $index, $label := .SortedPairs -}}\n {{ if $index }}, {{ end }}\n {{- $label.Name }}=\"{{ $label.Value -}}\"\n {{- end }}\n {{- end -}}\n )\n {{- end }}"
+        }
+    }],
+}
+
+# tests to verify the notifiers sending out the notifications with expected content
+NOTIFIERS_TEST = [
+    types.AlertManagerNotificationTestCase(
+        name="slack_notifier_default_templating",
+        rule_path="alerts/test_scenarios/threshold_above_at_least_once/rule.json",
+        alert_data=[
+            types.AlertData(
+                type="metrics",
+                data_path="alerts/test_scenarios/threshold_above_at_least_once/alert_data.jsonl",
+            ),
+        ],
+        channel_config=slack_default_config,
+        notification_expectation=types.AMNotificationExpectation(
+            should_notify=True,
+            wait_time_seconds=30,
+            notification_validations=[
+                types.NotificationValidation(
+                    destination_type="webhook",
+                    validation_data={
+                        "path": "/services/TEAM_ID/BOT_ID/TOKEN_ID",
+                        "json_body": {
+                            "attachments": [
+                                {
+                                "title": "[FIRING:1] threshold_above_at_least_once for  (alertname=\"threshold_above_at_least_once\", severity=\"critical\", threshold.name=\"critical\")",
+                                "text": "*Alert:* threshold_above_at_least_once - critical\r\n\r\n *Summary:* This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\r\n *Description:* This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\r\n *RelatedLogs:* \r\n *RelatedTraces:* \r\n\r\n *Details:*\r\n • *alertname:* threshold_above_at_least_once\r\n   • *severity:* critical\r\n   • *threshold.name:* critical\r\n   ",
+                            }]}
+                    },
+                ),
+            ],
+        ),
+    ),
+    types.AlertManagerNotificationTestCase(
+        name="msteams_notifier_default_templating",
+        rule_path="alerts/test_scenarios/threshold_above_at_least_once/rule.json",
+        alert_data=[
+            types.AlertData(
+                type="metrics",
+                data_path="alerts/test_scenarios/threshold_above_at_least_once/alert_data.jsonl",
+            ),
+        ],
+        channel_config=msteams_default_config,
+        notification_expectation=types.AMNotificationExpectation(
+            should_notify=True,
+            wait_time_seconds=30,
+            notification_validations=[
+                types.NotificationValidation(
+                    destination_type="webhook",
+                    validation_data={
+                        "path": "/msteams/webhook_url",
+                        "json_body": {
+                            "@context": "http://schema.org/extensions",
+                            "type": "MessageCard",
+                            "title": "[FIRING:1] threshold_above_at_least_once for  (alertname=\"threshold_above_at_least_once\", severity=\"critical\", threshold.name=\"critical\")",
+                            "text": "*Alert:* threshold_above_at_least_once - critical\r\n\r\n *Summary:* This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\r\n *Description:* This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\r\n *RelatedLogs:* \r\n *RelatedTraces:* \r\n\r\n *Details:*\r\n • *alertname:* threshold_above_at_least_once\r\n   • *severity:* critical\r\n   • *threshold.name:* critical\r\n   ",
+                            "themeColor": "8C1A1A"
+                        }
+                    },
+                ),
+            ],
+        ),
+    ),
+    types.AlertManagerNotificationTestCase(
+        name="pagerduty_notifier_default_templating",
+        rule_path="alerts/test_scenarios/threshold_above_at_least_once/rule.json",
+        alert_data=[
+            types.AlertData(
+                type="metrics",
+                data_path="alerts/test_scenarios/threshold_above_at_least_once/alert_data.jsonl",
+            ),
+        ],
+        channel_config=pagerduty_default_config,
+        notification_expectation=types.AMNotificationExpectation(
+            should_notify=True,
+            wait_time_seconds=30,
+            notification_validations=[
+                types.NotificationValidation(
+                    destination_type="webhook",
+                    validation_data={
+                        "path": "/v2/enqueue",
+                        "json_body": {
+                            "routing_key": "PagerDutyRoutingKey",
+                            "payload": {
+                                "summary": "[FIRING:1] threshold_above_at_least_once for  (alertname=\"threshold_above_at_least_once\", severity=\"critical\", threshold.name=\"critical\")",
+                                "custom_details": {
+                                "firing": {
+                                    "Annotations": [{"description = This alert is fired when the defined metric (current value": "15) crosses the threshold (10)"}],
+                                    "Labels": ["alertname = threshold_above_at_least_once","severity = critical","threshold.name = critical"],
+                                }}
+                            },
+                            "client": "SigNoz Alert Manager",
+                            "client_url": "https://enter-signoz-host-n-port-here/alerts"
+                            }
+                    },
+                ),
+            ],
+        ),
+    ),
+    types.AlertManagerNotificationTestCase(
+        name="opsgenie_notifier_default_templating",
+        rule_path="alerts/test_scenarios/threshold_above_at_least_once/rule.json",
+        alert_data=[
+            types.AlertData(
+                type="metrics",
+                data_path="alerts/test_scenarios/threshold_above_at_least_once/alert_data.jsonl",
+            ),
+        ],
+        channel_config=opsgenie_default_config,
+        notification_expectation=types.AMNotificationExpectation(
+            should_notify=True,
+            wait_time_seconds=30,
+            notification_validations=[
+                types.NotificationValidation(
+                    destination_type="webhook",
+                    validation_data={
+                        "path": "/v2/alerts",
+                        "json_body": {
+                            "message": "threshold_above_at_least_once",
+                            "description": "Alerts Firing:\r\n\t\r\n\t - Message: This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\r\n\tLabels:\r\n\t   - alertname = threshold_above_at_least_once\r\n\t   - severity = critical\r\n\t   - threshold.name = critical\r\n\t   Annotations:\r\n\t   - description = This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\r\n\t   - summary = This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\r\n\t   Source: \r\n\t\r\n",
+                            "details": {
+                                "alertname": "threshold_above_at_least_once",
+                                "severity": "critical",
+                                "threshold.name": "critical"
+                            },
+                            "priority": "P1"
+                        }
+                    },
+                ),
+            ],
+        ),
+    ),
+    types.AlertManagerNotificationTestCase(
+        name="webhook_notifier_default_templating",
+        rule_path="alerts/test_scenarios/threshold_above_at_least_once/rule.json",
+        alert_data=[
+            types.AlertData(
+                type="metrics",
+                data_path="alerts/test_scenarios/threshold_above_at_least_once/alert_data.jsonl",
+            ),
+        ],
+        channel_config=webhook_default_config,
+        notification_expectation=types.AMNotificationExpectation(
+            should_notify=True,
+            wait_time_seconds=30,
+            notification_validations=[
+                types.NotificationValidation(
+                    destination_type="webhook",
+                    validation_data={
+                        "path": "/webhook/webhook_url",
+                        "json_body": {
+                            "status": "firing",
+                            "alerts": [{
+                                "status": "firing",
+                                "labels": {"alertname": "threshold_above_at_least_once","severity": "critical","threshold.name": "critical"},
+                                "annotations": {"summary": "This alert is fired when the defined metric (current value: 15) crosses the threshold (10)"
+                                }}
+                            ],
+                            "commonLabels": {"alertname": "threshold_above_at_least_once","severity": "critical","threshold.name": "critical"},
+                            "commonAnnotations": {"summary": "This alert is fired when the defined metric (current value: 15) crosses the threshold (10)"}
+                            }
+                    },
+                ),
+            ],
+        ),
+    ),
+    types.AlertManagerNotificationTestCase(
+        name="email_notifier_default_templating",
+        rule_path="alerts/test_scenarios/threshold_above_at_least_once/rule.json",
+        alert_data=[
+            types.AlertData(
+                type="metrics",
+                data_path="alerts/test_scenarios/threshold_above_at_least_once/alert_data.jsonl",
+            ),
+        ],
+        channel_config=email_default_config,
+        notification_expectation=types.AMNotificationExpectation(
+            should_notify=True,
+            wait_time_seconds=30,
+            notification_validations=[
+                types.NotificationValidation(
+                    destination_type="email",
+                    validation_data={
+                        "subject": "[FIRING:1] threshold_above_at_least_once for  (alertname=\"threshold_above_at_least_once\", severity=\"critical\", threshold.name=\"critical\")",
+                        "html": "<html><body>*Alert:* threshold_above_at_least_once - critical\n\n *Summary:* This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\n *Description:* This alert is fired when the defined metric (current value: 15) crosses the threshold (10)\n *RelatedLogs:* \n *RelatedTraces:* \n\n *Details:*\n \u2022 *alertname:* threshold_above_at_least_once\n   \u2022 *severity:* critical\n   \u2022 *threshold.name:* critical\n   </body></html>"                    
+                    },
+                ),
+            ],
+        ),
+    ),
+]
+
+
+logger = setup_logger(__name__)
+
+@pytest.mark.parametrize(
+    "notifier_test_case",
+    NOTIFIERS_TEST,
+    ids=lambda notifier_test_case: notifier_test_case.name,
+)
+def test_notifier_templating(
+    # wiremock container for webhook notifications
+    notification_channel: types.TestContainerDocker,
+    # function to create wiremock mocks
+    make_http_mocks: Callable[[types.TestContainerDocker, List[Mapping]], None],
+    create_notification_channel: Callable[[dict], str],
+    # function to create alert rule
+    create_alert_rule: Callable[[dict], str],
+    # Alert data insertion related fixture
+    insert_alert_data: Callable[[List[types.AlertData], datetime], None],
+    # Mail dev container for email verification
+    maildev: types.TestContainerDocker,
+    # test case from parametrize
+    notifier_test_case: types.AlertManagerNotificationTestCase,
+):
+    # generate unique channel name
+    channel_name = str(uuid.uuid4())
+
+    # update channel config: set name and rewrite URLs to wiremock
+    channel_config = update_channel_config_urls(
+        notifier_test_case.channel_config, notification_channel
+    )
+    channel_config["name"] = channel_name
+
+    # setup wiremock mocks for webhook-based validations
+    webhook_validations = [
+        v
+        for v in notifier_test_case.notification_expectation.notification_validations
+        if v.destination_type == "webhook"
+    ]
+    mock_mappings = [
+        Mapping(
+            request=MappingRequest(
+                method=HttpMethods.POST, url=v.validation_data["path"]
+            ),
+            response=MappingResponse(status=200, json_body={}),
+            persistent=False,
+        )
+        for v in webhook_validations
+    ]
+    if mock_mappings:
+        make_http_mocks(notification_channel, mock_mappings)
+        logger.info("Mock mappings created: %s", {"mock_mappings": mock_mappings})
+
+    # create notification channel
+    create_notification_channel(channel_config)
+    logger.info("Channel created with name: %s", {"channel_name": channel_name})
+
+    # insert alert data
+    insert_alert_data(
+        notifier_test_case.alert_data,
+        base_time=datetime.now(tz=timezone.utc) - timedelta(minutes=5),
+    )
+
+    # create alert rule
+    rule_path = get_testdata_file_path(notifier_test_case.rule_path)
+    with open(rule_path, "r", encoding="utf-8") as f:
+        rule_data = json.loads(f.read())
+    update_rule_channel_name(rule_data, channel_name)
+    rule_id = create_alert_rule(rule_data)
+    logger.info(
+        "rule created: %s", {"rule_id": rule_id, "rule_name": rule_data["alert"]}
+    )
+
+    # verify notification expectations
+    verify_notification_expectation(
+        notification_channel,
+        maildev,
+        notifier_test_case.notification_expectation,
+    )

tests/integration/src/alertmanager/conftest.py

@@ -0,0 +1,41 @@
+from fixtures import types
+
+from fixtures.signoz import create_signoz
+import pytest
+from testcontainers.core.container import Network
+
+@pytest.fixture(name="signoz", scope="package")
+def signoz(  # pylint: disable=too-many-arguments,too-many-positional-arguments
+    network: Network,
+    zeus: types.TestContainerDocker,
+    gateway: types.TestContainerDocker,
+    sqlstore: types.TestContainerSQL,
+    clickhouse: types.TestContainerClickhouse,
+    request: pytest.FixtureRequest,
+    pytestconfig: pytest.Config,
+    maildev: types.TestContainerDocker,
+    notification_channel: types.TestContainerDocker,
+) -> types.SigNoz:
+    """
+    Package-scoped fixture for setting up SigNoz.
+    Overrides SMTP, PagerDuty, and OpsGenie URLs to point to test containers.
+    """
+    return create_signoz(
+        network=network,
+        zeus=zeus,
+        gateway=gateway,
+        sqlstore=sqlstore,
+        clickhouse=clickhouse,
+        request=request,
+        pytestconfig=pytestconfig,
+        env_overrides={
+            # SMTP config for email notifications via maildev
+            "SIGNOZ_ALERTMANAGER_SIGNOZ_GLOBAL_SMTP__SMARTHOST": f"{maildev.container_configs['1025'].address}:{maildev.container_configs['1025'].port}",
+            "SIGNOZ_ALERTMANAGER_SIGNOZ_GLOBAL_SMTP__REQUIRE__TLS": "false",
+            "SIGNOZ_ALERTMANAGER_SIGNOZ_GLOBAL_SMTP__FROM": "alertmanager@signoz.io",
+            # PagerDuty API URL -> wiremock (default: https://events.pagerduty.com/v2/enqueue)
+            "SIGNOZ_ALERTMANAGER_SIGNOZ_GLOBAL_PAGERDUTY__URL": notification_channel.container_configs["8080"].get("/v2/enqueue"),
+            # OpsGenie API URL -> wiremock (default: https://api.opsgenie.com/)
+            "SIGNOZ_ALERTMANAGER_SIGNOZ_GLOBAL_OPSGENIE__API__URL": notification_channel.container_configs["8080"].get("/"),
+        },
+    )