diff --git a/src/react-app-env.d.ts b/src/react-app-env.d.ts
index 69ee57a..5f86bb0 100644
--- a/src/react-app-env.d.ts
+++ b/src/react-app-env.d.ts
@@ -1,5 +1,71 @@
 /// <reference types="react-scripts" />
 
+// TODO: Contribute this to DefinitelyTyped
 declare module 'trystero' {
-  export function joinRoom(config: any, ns: any): any
+  export interface RoomConfig {}
+
+  export type PeerActionData = any
+
+  export interface Room {
+    makeAction: (
+      namespace: string
+    ) => [
+      (
+        data: PeerActionData,
+        targetPeers?: string[],
+        metadata?: Record,
+        progress: (percent: number, peerId: string) => void
+      ) => void,
+
+      (data: PeerActionData, peerId: string, metadata?: Record) => void,
+
+      (percent: number, peerId: string, metadata?: Record) => void
+    ]
+
+    ping: (id: string) => Promise<number>
+
+    leave: () => void
+
+    getPeers: () => string[]
+
+    addStream: (
+      stream: MediaStream,
+      peerId?: string,
+      metadata?: Record
+    ) => Promise<void>[]
+
+    removeStream: (stream: MediaStream, peerId?: string) => void
+
+    addTrack: (
+      track: MediaStreamTrack,
+      stream: MediaStream,
+      peerId?: string,
+      metadata?: Record
+    ) => Promise<void>[]
+
+    removeTrack: (
+      track: MediaStreamTrack,
+      stream: MediaStream,
+      peerId?: string
+    ) => void
+
+    replaceTrack: (
+      oldTrack: MediaStreamTrack,
+      newTrack: MediaStreamTrack,
+      stream: MediaStream,
+      peerId?: string
+    ) => Promise<void>[]
+
+    onPeerJoin: (fn: (peerId: string) => void) => void
+
+    onPeerLeave: (fn: (peerId: string) => void) => void
+
+    onPeerStream: (fn: (stream: MediaStream, peerId: string) => void) => void
+
+    onPeerTrack: (
+      fn: (track: MediaStreamTrack, stream: MediaStream, peerId: string) => void
+    ) => void
+  }
+
+  export function joinRoom(config: RoomConfig, roomId: string): Room
 }