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WebSocket Debugger online

Test WebSocket connections — connect, send messages, watch the live log

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Disconnected
// Message logsent=■ received=■ error=■
--:--:--Waiting for connection...

How to Use WebSocket Debugger

  1. Enter a WebSocket URL starting with ws:// (unencrypted) or wss:// (secure, TLS-encrypted) into the URL field. The default is wss://echo.websocket.org — a public echo server that bounces every message straight back.
  2. Click Connect. The status dot turns green and the log shows a "Connected" entry when the handshake succeeds.
  3. Type any message — plain text, JSON, or a command string — in the Send field and press Send or hit Enter.
  4. Watch the colour-coded log: sent frames appear in blue, received frames in lime green, connection events in grey, and errors in red. Each entry is timestamped to the second.

This free browser-based WebSocket tester is a lightweight alternative to tools like Postman's WebSocket client or wscat on the command line. It is useful for debugging real-time APIs, testing socket.io endpoints, verifying chat server behaviour, checking push notification streams, and confirming that a WebSocket server is alive and responding before writing application code.

How WebSocket Debugger Works

WebSocket Debugger uses the browser's built-in WebSocket API (defined in RFC 6455) to establish a persistent, full-duplex connection to the target server. No proxy, no third-party relay — your browser connects directly. The tool listens on the socket's onmessage, onopen, onerror, and onclose events and renders each event as a timestamped log entry. Because everything runs in your browser, this tool works on any OS and any device that has a modern browser.

Frequently Asked Questions

What is a WebSocket?

WebSocket is a persistent, full-duplex communication protocol over a single TCP connection, standardised in RFC 6455. Unlike HTTP (which is request-response and closes after each exchange), a WebSocket connection stays open so both the client and server can send frames at any time without polling. Common use cases include real-time chat applications, live sports scores, collaborative editing, stock price feeds, multiplayer games, IoT device monitoring, and server-sent push notifications.

What is the difference between ws:// and wss://?

ws:// is plain, unencrypted WebSocket — analogous to HTTP. wss:// is WebSocket Secure, encrypted with TLS — analogous to HTTPS. All production systems should use wss:// to protect message content in transit. Browsers served over HTTPS will block mixed-content connections to ws:// endpoints, so you will see a connection error if you try to reach a plain WebSocket from a secure page.

Why does my WebSocket connection fail?

Common causes of WebSocket connection failures: the server is offline or the URL is incorrect; the server requires token-based authentication (e.g. a ?token= query parameter) that the URL is missing; the server's CORS or origin policy rejects connections from this domain; the server requires a specific subprotocol that is not negotiated; or the server uses a self-signed TLS certificate that the browser refuses. Check the error log entry for the close code — it often points to the specific cause.

Can I send JSON over WebSocket?

Yes — WebSocket frames carry arbitrary UTF-8 text or raw binary data. JSON is the most widely used message format for WebSocket APIs (especially with socket.io and GraphQL subscriptions). Paste your JSON string directly into the message field and click Send — this tool transmits the raw text as-is. Many APIs also accept MessagePack (binary) or newline-delimited JSON; for those, send the encoded text representation.

Explore the full suite of Network tools — including DNS Lookup, HTTP Request Tester, and 310+ other free utilities — at Chunky Munster.

📖 Reference: RFC 6455 — The WebSocket Protocol