Your files stay on your device

# WebSocket Tester

Connect a WebSocket in your browser: subprotocols, frames, close codes, timeouts.
ConnectWebSocket URLSubprotocols (comma-separated)

Browsers set only the protocol, never custom headers.
Connect timeout (ms)

Browser egress

The browser opens the WebSocket you name directly. No server hop, exactly your browser's own client behavior. This page leaves your browser only when you press the button; never on load, never in the background. Nothing is sent anywhere else, and no analytics loads on this page.

Phase: idle

0 sent ( 0 B) · 0 received ( 0 B)
Text frame to sendSend frame

No frames yet: connect, then send. Received binary frames are shown as hex.

What the browser will not do, stated up front: custom handshake headers cannot be set, the handshake's response headers cannot be read, and ping/pong control frames are handled by the browser without a script API.
Nothing in yet

Paste, drop, or type to begin. Everything stays on this device.

## Next door in Network

- [HTTP timing probe](/network/http-timing)
- [Live HTTP headers](/network/headers)
[All network tools](/network)

---

Canonical HTML: https://nutter.tools/network/ws-tester
Markdown version: https://nutter.tools/network/ws-tester/index.md
Plain-text version: https://nutter.tools/network/ws-tester/index.txt
Agent index: https://nutter.tools/llms.txt