diff --git a/src/server/socket.ts b/src/server/socket.ts
index 64d7d0e..9305bc4 100644
--- a/src/server/socket.ts
+++ b/src/server/socket.ts
@@ -1,13 +1,11 @@
 'use strict'
 import _debug from 'debug'
 import map from 'lodash/map'
-import { Socket, Server } from 'socket.io'
+import { ServerSocket, TypedIO } from '../shared'
 
 const debug = _debug('peercalls:socket')
 
-type SocketWithRoom = Socket & { room?: string }
-
-export default function handleSocket(socket: SocketWithRoom, io: Server) {
+export default function handleSocket(socket: ServerSocket, io: TypedIO) {
   socket.on('signal', payload => {
     // debug('signal: %s, payload: %o', socket.id, payload)
     io.to(payload.userId).emit('signal', {
diff --git a/src/shared/SocketEvent.ts b/src/shared/SocketEvent.ts
new file mode 100644
index 0000000..1014233
--- /dev/null
+++ b/src/shared/SocketEvent.ts
@@ -0,0 +1,28 @@
+import { TypedEmitter, TypedEmitterKeys } from './TypedEmitter'
+
+export interface User {
+  id: string
+}
+
+export interface SocketEvent {
+  users: {
+    initiator: string
+    users: User[]
+  }
+  signal: {
+    userId: string
+    signal: unknown
+  }
+  connect: void
+  disconnect: void
+  ready: string
+}
+
+export type ServerSocket =
+  Omit<SocketIO.Socket, TypedEmitterKeys> &
+  TypedEmitter<SocketEvent> &
+  { room?: string }
+
+export type TypedIO = SocketIO.Server & {
+  to(roomName: string): TypedEmitter<SocketEvent>
+}
diff --git a/src/shared/TypedEmitter.ts b/src/shared/TypedEmitter.ts
index 6dd7acb..f761220 100644
--- a/src/shared/TypedEmitter.ts
+++ b/src/shared/TypedEmitter.ts
@@ -5,6 +5,14 @@ type Callback<A> = (a: A) => void
 // eslint-disable-next-line
 type Events = Record<string | symbol, any>
 
+export type TypedEmitterKeys =
+  'addListener' |
+  'removeListener' |
+  'on' |
+  'once' |
+  'off' |
+  'emit'
+
 export interface TypedEmitter<E extends Events>
 extends EventEmitter {
   addListener<K extends keyof E>(t: K, callback: Callback<E[K]>): this
diff --git a/src/shared/index.ts b/src/shared/index.ts
new file mode 100644
index 0000000..231f83e
--- /dev/null
+++ b/src/shared/index.ts
@@ -0,0 +1,2 @@
+export * from './SocketEvent'
+export * from './TypedEmitter'