WebSocket Client
Connect to WebSocket servers, send and receive messages in real-time — test your WebSocket APIs in the browser
Messages
What is WebSocket Client?
WebSocket Client is a free browser-based tool for connecting to WebSocket servers, sending and receiving messages in real-time. It supports custom subprotocols, auto-reconnect, ping intervals, and message filtering. The tool displays messages with timestamps and direction indicators, supports JSON formatting for structured messages, and maintains a complete message log. All connections go directly from your browser to the target WebSocket server with no data proxied through this site. Essential for testing WebSocket APIs, debugging real-time features, and understanding WebSocket communication.
How to Use
- Enter the WebSocket server URL (ws:// or wss://).
- Optionally configure subprotocol, auto-reconnect, and ping interval in settings.
- Click Connect to establish a WebSocket connection.
- Type a message and click Send or press Ctrl+Enter to send it.
Tips & Best Practices
- Use the 'Try it' button to connect to an echo server and understand how WebSocket messaging works.
- Enable auto-reconnect when testing servers that may restart or drop connections.
- Use JSON format mode for structured message inspection when working with GraphQL subscriptions or STOMP.
- Filter messages by sent/received to focus on specific communication direction.
- Set a ping interval to keep connections alive with servers that have idle timeout policies.
Use Cases
API Testing
Test WebSocket server endpoints during development to verify message handling.
Real-time Features
Debug chat applications, live notifications, and streaming data feeds.
GraphQL Subscriptions
Test GraphQL subscription endpoints using the graphql-ws subprotocol.
IoT Development
Test communication with IoT devices and services that use WebSocket protocols.
FAQ
Why can't I connect to some WebSocket servers?
The server might not support WebSocket, the URL might be wrong, or the server may require specific subprotocols. Unlike HTTP CORS, WebSocket connections are generally not restricted by the browser, but the server can reject connections based on origin.
What is a subprotocol?
A WebSocket subprotocol is a custom protocol that runs on top of WebSocket, such as graphql-ws for GraphQL subscriptions or stomp for message queuing. Leave it empty if your server doesn't require one.
What is WebSocket?
WebSocket is a protocol that enables full-duplex, real-time communication between client and server over a single TCP connection, commonly used for chat and live notifications.
Does my message data pass through this site's server?
No, the WebSocket connection is established directly from your browser to the target server. This site does not relay or store any communication.
What is the difference between ws:// and wss://?
ws:// is an unencrypted connection, while wss:// is a TLS-encrypted secure connection. Using wss:// is recommended for production environments.
What is the difference between WebSocket and HTTP?
HTTP uses a request-response model for one-way communication, while WebSocket supports bidirectional communication where both server and client can freely send messages as long as the connection is open.
Is my data collected?
No, all connections go directly from your browser to the WebSocket server. No data is proxied through this site.
What URL schemes are supported?
Both ws:// (unencrypted) and wss:// (encrypted, recommended) are supported.
Why does my connection keep dropping?
The server may have idle timeout policies. Enable auto-reconnect and set a ping interval to keep the connection alive.
Can I send binary messages?
This tool supports text and JSON messages. For binary WebSocket testing, use specialized development tools.
What is auto-reconnect?
Auto-reconnect automatically re-establishes the WebSocket connection when it drops, useful for testing unstable connections.
How is this different from the REST Client?
REST Client sends one-time HTTP requests. WebSocket Client maintains a persistent two-way connection for real-time messaging.