diff --git a/README.md b/README.md
index eb628ca..2d024de 100644
--- a/README.md
+++ b/README.md
@@ -121,8 +121,9 @@ import { YSocketIO } from 'y-socket.io/dist/server'
 ```js
 configuration = {
   // Optionally, set here the authentication validation callback (by default server accepts all connections)
-  // (for example: if client sent a token, you can get token from auth object 
-  authenticate: undefined, // Example: (auth) => auth.token === 'valid-token')
+  // For example: if client sent a token or other data, you can get it from auth object of 
+  //              socket.io handshake
+  authenticate: undefined, // Example: (handshake) => handshake.auth.token === 'valid-token')
   // Optionally, enable LevelDB persistence by setting the directory where you want to store the database (by default the LevelDB persistence is disabled)
   levelPersistenceDir: undefined,
   // Enable/Disable garbage collection (by default the garbage collection is enabled)
diff --git a/examples/react-example/src/App.tsx b/examples/react-example/src/App.tsx
index 276f340..ddf7ee1 100644
--- a/examples/react-example/src/App.tsx
+++ b/examples/react-example/src/App.tsx
@@ -5,7 +5,7 @@ import { SocketIOProvider } from 'y-socket.io';
 function App() {
   const [doc, setDoc] = useState<Y.Doc | null>(null);
   const [provider, setProvider] = useState<SocketIOProvider | null>(null);
-  const [connected, setConnected] = useState<boolean>(true);
+  const [status, setStatus] = useState<string>('disconnected');
   const [input, setInput] = useState<string>('');
   const [clients, setClients] = useState<string[]>([]);
 
@@ -37,10 +37,9 @@ function App() {
         });
       socketIOProvider.awareness.on('change', () => setClients(Array.from(socketIOProvider.awareness.getStates().keys()).map(key => `${key}`)))
       socketIOProvider.awareness.setLocalState({ id: Math.random(), name: 'Perico' });
-      socketIOProvider.on('sync', (status: boolean) => console.log('websocket sync', status))
-      socketIOProvider.on('status', ({ status }: { status: string }) => {
-        if (status === 'connected') setConnected(true);
-        else setConnected(false);
+      socketIOProvider.on('sync', (isSync: boolean) => console.log('websocket sync', isSync))
+      socketIOProvider.on('status', ({ status: _status }: { status: string }) => {
+        if (!!_status) setStatus(_status);
       })
       setProvider(socketIOProvider);
     }
@@ -58,9 +57,9 @@ function App() {
     <div>
       App
       <div style={{ color: 'white' }}>
-        <p>State: {connected ? 'Connected' : 'Disconneted'}</p>
+        <p>State: {status}</p>
         {
-          !connected
+          !(status === 'connected')
             ? <>
               <button onClick={() => provider.connect()}>Connect</button>
             </>
diff --git a/src/client/provider.ts b/src/client/provider.ts
index c0ecfc4..2545bac 100644
--- a/src/client/provider.ts
+++ b/src/client/provider.ts
@@ -242,7 +242,7 @@ export class SocketIOProvider extends Observable<string> {
    * Connect provider's socket
    * @type {() => void}
    */
-  public connect (): void {
+  public connect(): void {
     if (!this.socket.connected) {
       this.emit('status', [{ status: 'connecting' }])
       this.socket.connect()
diff --git a/src/server/server.ts b/src/server/server.ts
index 374a79a..2d5a800 100644
--- a/src/server/server.ts
+++ b/src/server/server.ts
@@ -21,7 +21,14 @@ const io = new Server(server)
 //       for other logic, these do not match the regular expression, this could cause unwanted problems.
 // TIP: You can export a new instance from another file to manage as singleton and access documents from all app.
 const ysocketio = new YSocketIO(io, {
-  // authenticate: (auth) => auth.token === 'valid-token',
+  // authenticate: (handshake) => handshake.auth.token === 'valid-token',
+  // OR
+  // authenticate: (handshake) => {
+  //   return new Promise<boolean>(resolve => {
+  //     setTimeout(() => resolve(handshake.auth.token === 'valid-token'), 2000)
+  //   })
+  // },
+  
   // levelPersistenceDir: './storage-location',
   // gcEnabled: true,
 })
diff --git a/src/server/y-socket-io.ts b/src/server/y-socket-io.ts
index 8c3591c..ab58876 100644
--- a/src/server/y-socket-io.ts
+++ b/src/server/y-socket-io.ts
@@ -32,10 +32,10 @@ export interface YSocketIOConfiguration {
   /**
    * Callback to authenticate the client connection.
    *
-   *  If it returns true, the connection is allowed; otherwise, if it returns false, the connection is rejected.
-   * @param auth Provided from the auth attribute on the socket io handshake
+   *  It can be a promise and if it returns true, the connection is allowed; otherwise, if it returns false, the connection is rejected.
+   * @param handshake Provided from the handshake attribute of the socket io
    */
-  authenticate?: (auth: { [key: string]: any }) => boolean
+  authenticate?: (handshake: { [key: string]: any }) => Promise<boolean> | boolean
 }
 
 /**
@@ -92,9 +92,9 @@ export class YSocketIO extends Observable<string>  {
   public initialize (): void {
     const dynamicNamespace = this.io.of(/^\/yjs\|.*$/)
 
-    dynamicNamespace.use((socket, next) => {
+    dynamicNamespace.use(async (socket, next) => {
       if ((this.configuration?.authenticate) == null) return next()
-      if (this.configuration.authenticate(socket.handshake.auth)) return next()
+      if (await this.configuration.authenticate(socket.handshake)) return next()
       else return next(new Error('Unauthorized'))
     })