diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..0ad7a14
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,71 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+/// <reference types="node" />
+import { Server } from "net";
+import EventEmitter from "events";
+import WebSocketLib from "ws";
+import Express from "express";
+
+declare type MyWebSocket = WebSocketLib & EventEmitter;
+
+declare type Optional<T> = {
+  [P in keyof T]?: (T[P] | undefined);
+};
+
+declare interface IConfig {
+  readonly port: number;
+  readonly expire_timeout: number;
+  readonly alive_timeout: number;
+  readonly key: string;
+  readonly path: string;
+  readonly concurrent_limit: number;
+  readonly allow_discovery: boolean;
+  readonly proxied: boolean | string;
+  readonly cleanup_out_msgs: number;
+  readonly ssl?: {
+    key: string;
+    cert: string;
+  };
+  readonly generateClientId?: () => string;
+}
+
+declare interface IClient {
+  getId(): string;
+  getToken(): string;
+  getSocket(): MyWebSocket | null;
+  setSocket(socket: MyWebSocket | null): void;
+  getLastPing(): number;
+  setLastPing(lastPing: number): void;
+  send(data: any): void;
+}
+
+declare enum MessageType {
+  OPEN = "OPEN",
+  LEAVE = "LEAVE",
+  CANDIDATE = "CANDIDATE",
+  OFFER = "OFFER",
+  ANSWER = "ANSWER",
+  EXPIRE = "EXPIRE",
+  HEARTBEAT = "HEARTBEAT",
+  ID_TAKEN = "ID-TAKEN",
+  ERROR = "ERROR"
+}
+
+declare interface IMessage {
+  readonly type: MessageType;
+  readonly src: string;
+  readonly dst: string;
+  readonly payload?: any;
+}
+
+declare interface CustomExpress extends Express.Express {
+  on(event: string, callback: (...args: any[]) => void): this;
+  on(event: 'connection', callback: (client: IClient) => void): this;
+  on(event: 'disconnect', callback: (client: IClient) => void): this;
+  on(event: 'message', callback: (client: IClient, message: IMessage) => void): this;
+  on(event: 'error', callback: (error: Error) => void): this;
+}
+
+declare function ExpressPeerServer(server: Server, options?: IConfig): CustomExpress;
+declare function PeerServer(options?: Optional<IConfig>, callback?: (server: Server) => void): CustomExpress;
+
+export { ExpressPeerServer, PeerServer };
diff --git a/package.json b/package.json
index ca04c2c..822fa77 100644
--- a/package.json
+++ b/package.json
@@ -8,7 +8,8 @@
   },
   "files": [
     "bin/",
-    "dist/"
+    "dist/",
+    "index.d.ts"
   ],
   "repository": {
     "type": "git",