WebSocket Tester
Test WebSocket connections, send and receive messages, inspect lifecycle events, and debug connection issues in real time.
Browsers do not support custom WebSocket headers. Use query params, cookies, or subprotocols instead.
Status
Disconnected
Duration
00:00:00
Protocol
—
Connected
—
Sent
0
Received
0
Send Message
Messages
Real-time Testing
Connect to any ws:// or wss:// endpoint, send messages, and see responses as they arrive.
Lifecycle Visibility
Track connection state, close codes, error events, duration, and message counters in one view.
Error Diagnosis
Get human-readable explanations for close codes, mixed-content errors, and connection failures.
WebSocket Tester Guide
What are WebSockets?
WebSocket is a communication protocol that provides full-duplex communication channels over a single TCP connection. Unlike HTTP, which follows a request-response model, WebSockets allow both the client and server to send messages independently at any time, making them ideal for real-time applications like chat, live updates, gaming, and streaming.
When to use WebSockets
WebSockets are best suited for applications that need real-time, bidirectional communication — chat applications, live dashboards, collaborative editing, multiplayer games, financial tickers, and IoT data streams. For simple one-directional updates, Server-Sent Events (SSE) may be a lighter alternative.
Common WebSocket issues
Connection failures are often caused by firewall or proxy blocking, incorrect URLs, CORS/origin restrictions, or servers that don't support the WebSocket upgrade handshake. HTTPS sites must use wss:// (not ws://) to avoid mixed-content errors. Close code 1006 typically means the connection was dropped unexpectedly — check server health and network stability.
WebSocket close codes
The WebSocket protocol defines standard close codes: 1000 (Normal Closure), 1001 (Going Away), 1002 (Protocol Error), 1003 (Unsupported Data), 1006 (Abnormal Closure — no close frame received), 1008 (Policy Violation), and 1011 (Internal Server Error). This tool displays the close code and a human-readable explanation when a connection ends.
Browser limitations
The browser WebSocket API does not allow setting custom HTTP headers on the handshake request. To pass authentication tokens or metadata, use URL query parameters, cookies, or the Sec-WebSocket-Protocol subprotocol header. This is a browser security restriction and applies to all WebSocket clients running in a browser context.
Privacy
This tool runs entirely in your browser. WebSocket messages travel directly between your browser and the target server. No data is stored, logged, or proxied through any intermediary. Base64 is encoding, not encryption — treat sensitive payloads accordingly.