How to use WebSocket in flutter step by step guide

Using WebSockets in Flutter allows you to create real-time communication between the client (Flutter app) and a server. Flutter provides WebSocket support via the web_socket_channel package.

Here’s a step-by-step guide to using WebSockets in Flutter:

Step 1: Add Dependency

Open your pubspec.yaml file and add:

dependencies:
  flutter:
    sdk: flutter
  web_socket_channel: ^2.4.0  # Check for latest version on pub.dev

Then run:

flutter pub get

---

Step 2: Import the Package

In your Dart file:

import 'package:web_socket_channel/web_socket_channel.dart';

---

Step 3: Connect to a WebSocket Server

You can connect using:

final channel = WebSocketChannel.connect(
  Uri.parse('wss://echo.websocket.org'), // Replace with your WebSocket server
);

Use ws:// for unencrypted connection and wss:// for secure (SSL/TLS) connection.

---

Step 4: Listen to Incoming Messages

channel.stream.listen(
  (message) {
    print('Received: $message');
  },
  onError: (error) {
    print('Error: $error');
  },
  onDone: () {
    print('WebSocket closed');
  },
);

---

Step 5: Send Messages

channel.sink.add('Hello WebSocket!');

---

Step 6: Close the WebSocket Connection

Always close the socket when you’re done:

channel.sink.close();

---

Full Example (Minimal App)

import 'package:flutter/material.dart';
import 'package:web_socket_channel/web_socket_channel.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  final WebSocketChannel channel = WebSocketChannel.connect(
    Uri.parse('wss://echo.websocket.events'), // Test server
  );

  @override
  Widget build(BuildContext context) {
    final TextEditingController controller = TextEditingController();

    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('WebSocket Demo')),
        body: Padding(
          padding: const EdgeInsets.all(20.0),
          child: Column(
            children: [
              TextField(controller: controller),
              ElevatedButton(
                child: Text('Send'),
                onPressed: () {
                  if (controller.text.isNotEmpty) {
                    channel.sink.add(controller.text);
                  }
                },
              ),
              SizedBox(height: 20),
              StreamBuilder(
                stream: channel.stream,
                builder: (context, snapshot) {
                  return Text(snapshot.hasData ? 'Received: ${snapshot.data}' : '');
                },
              ),
            ],
          ),
        ),
      ),
    );
  }
}

---

Tips

• Use StreamBuilder to reactively update your UI with WebSocket messages.
• Always handle connection errors gracefully.
• Secure your WebSocket server with authentication if used in production.
• You can reconnect logic using retry or state management.

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