diff --git a/package.json b/package.json
index b820421..c0467da 100644
--- a/package.json
+++ b/package.json
@@ -9,6 +9,7 @@
   "files": [
     "src"
   ],
+  "types": "src/index.d.ts",
   "exports": {
     "require": "./src/index.js",
     "import": "./src/index.mjs"
diff --git a/src/index.d.ts b/src/index.d.ts
new file mode 100644
index 0000000..f8b53cb
--- /dev/null
+++ b/src/index.d.ts
@@ -0,0 +1,74 @@
+import * as ws from 'ws';
+import * as uWS from 'uWebSockets.js';
+import {IncomingMessage} from 'http';
+
+declare namespace WebSocket {
+    type HandleUpgradeResult<T, U> = (ws: T, request: U) => void | false | void;
+
+    interface ServerOptions<
+        T extends typeof WebSocketClient = typeof WebSocketClient,
+        U extends typeof IncomingMessage = typeof IncomingMessage,
+    > extends Omit<ws.ServerOptions<T, U>, 'noServer' | 'skipUTF8Validation' | 'backlog'> {
+        // pass true for DEDICATED_COMPRESSOR_4KB | DEDICATED_DECOMPRESSOR or your own CompressOptions number.
+        // Options are not supported and if this is an object it will be treated as true.
+        // https://github.com/uNetworking/uWebSockets.js/blob/master/docs/index.d.ts#L360-L361
+        perMessageDeflate?: boolean | uWS.CompressOptions | ws.PerMessageDeflateOptions;
+
+        uwsOptions?: uWS.AppOptions;
+
+        /**
+         * Custom upgrade handler
+         * By default (handleUpgrade: undefined), the connection will be handled as usual, and "connection" event will be emitted.
+         * @returns 
+         *  - function: Callback to handle the WebSocket instance manually
+         *  - false: Reject the connection (remember to destroy the socket)
+         *  - void/other: Handle normally, will emit 'connection' event
+         */
+        handleUpgrade?: (request: T) => Promise<HandleUpgradeResult<T, U>> | HandleUpgradeResult<T, U>;
+    }
+
+    class WebSocketServer<
+        T extends typeof WebSocketClient = typeof WebSocketClient,
+        U extends typeof IncomingMessage = typeof IncomingMessage,
+    > extends ws.Server<T, U> {
+        constructor(options: WebSocket.ServerOptions<T, U>);
+
+        // Override ws.Server's handleUpgrade to prevent usage
+        // passing a custom handleUpgrade function in constructor option for alternatives.
+        override handleUpgrade: never;
+    }
+
+    type SendReturnType = 0 | 1 | 2;
+    interface SendOptions {
+        binary?: boolean;
+        compress?: boolean;
+    }
+
+    class WebSocketClient extends ws.WebSocket {
+        /**
+         * Send a message. Support binary/compress options only.
+         * Callback will only get error if it returns 2
+         * @returns 
+         *  - 1 for success
+         *  - 2 for dropped due to backpressure limit
+         *  - 0 for built up backpressure that will drain over time.
+         */
+        override send(
+            message: uWS.RecognizedString,
+            callback?: (err?: Error) => void,
+        ): SendReturnType; 
+        override send(
+            message: uWS.RecognizedString,
+            options: SendOptions, callback?: (err?: Error) => void,
+        ): SendReturnType;
+
+        override ping(data?: uWS.RecognizedString): void;
+        override pong(): void;
+    }
+}
+
+export = {
+    ...ws,
+    Server: WebSocket.WebSocketServer,
+    WebSocketServer: WebSocket.WebSocketServer,
+};
\ No newline at end of file