WebSocket Test Client

WebSocket is a full-duplex communication protocol over a single TCP connection. Unlike HTTP, which is request-response (client always initiates), WebSocket allows both the server and client to send messages at any time. The connection starts with an HTTP upgrade handshake, then switches to the WebSocket protocol. This makes it ideal for real-time features like live dashboards, chat, gaming, and push notifications.

ws:// is unencrypted WebSocket — traffic can be intercepted in transit. wss:// is WebSocket over TLS (like HTTPS for HTTP). Always use wss:// in production. Browsers running on HTTPS pages block mixed-content ws:// connections, so if your app is on HTTPS, your WebSocket server must also use wss://.

Unlike HTTP requests, WebSocket connections don't use the same CORS mechanism. The server controls access via the Origin header during the upgrade handshake. If the server rejects your origin, you'll see a 403 or connection refused. This tool sends your browser's origin, so the server sees a request from devplaybook.cc. For local testing, use a server that accepts all origins or run the tool from a matching origin.

When a WebSocket connection closes, a close code indicates why. Common codes: 1000 = normal closure, 1001 = endpoint going away (server restart), 1006 = abnormal closure (no close frame received, often a network error), 1011 = server internal error, 1013 = service restart, 1015 = TLS failure. Codes 4000–4999 are reserved for application-defined use. A 1006 code usually means the connection was dropped unexpectedly — check server logs.

Start your WebSocket server (e.g., on ws://localhost:8080), then use this tool to connect. Note: browser security may block ws:// connections to localhost from an HTTPS page. Use a locally-run dev server or try the wss:// version with a self-signed cert. Alternatively, use a public echo server like wss://echo.websocket.events to verify the tool itself works before debugging your server.

WebSocket carries raw bytes — the framing is binary or text. In practice, most APIs use JSON text frames. Some use MessagePack (binary), Protobuf, or plain text. This tool sends messages as UTF-8 text. If your server expects binary frames or a specific encoding, you may need a native client or a custom test script using Node.js's ws library.