diff --git a/server/src/io.ts b/server/src/io.ts
new file mode 100644
index 000000000..4d5dfd74b
--- /dev/null
+++ b/server/src/io.ts
@@ -0,0 +1,23 @@
+import { Server, Socket } from "engine.io";
+
+export type IOServer<T> = {
+    on(ev: 'connection' | 'drain', fn: (socket: IOSocket & T) => void): IOServer<T>;
+} & Server;
+
+export type IOSocket = {
+    send(data: any, options?: any, callback?: any): IOSocket;
+
+    on(ev: "close", fn: (reason: string, description?: Error) => void): IOSocket;
+    /**
+     * Fired when the client sends a message.
+     */
+    on(ev: "message", fn: (data: string | Buffer) => void): IOSocket;
+    /**
+     * Fired when an error occurs.
+     */
+    on(ev: "error", fn: (err: Error) => void): IOSocket;
+    /**
+     * Called when the write buffer is drained
+     */
+    on(ev: "drain", fn: () => void): IOSocket;
+};