Developer / Network
WebSocket Tester
Connect to a WebSocket server from your browser, send messages, watch everything that arrives in a timed log with JSON formatting, and repeat a message as a keep-alive.
WebSocket Tester: The tester opens a WebSocket connection directly from your browser to the server you name, so messages never pass through this site. It shows when the connection opens, every message in both directions with a timestamp, errors, and the close code and reason. Received JSON can be shown formatted, and a message can be sent again every few seconds to keep an idle connection open. Runs 100% locally in your browser with zero server file uploads.
- Category
- Developer tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
The connection goes straight from your browser to the server; messages do not pass through this site. Browsers cannot send WebSocket protocol pings, so the repeat option sends your message as a keep-alive instead.
Debugging a WebSocket server
If the connection closes at once with code 1006, the server probably rejected the HTTP upgrade: check the path, that it accepts this page's origin, and any authentication it expects, often a token in the URL's query string, since browsers cannot add custom headers to WebSocket requests.
For ordinary HTTP endpoints, check status codes with the HTTP status checker, or turn a curl command into code with cURL to code.
Keeping connections alive
Proxies and load balancers often close idle connections after 30 to 120 seconds. Servers usually send protocol pings to prevent this; when testing from a browser, sending a small message every 30 seconds does the same job.
How to use it
- Enter a wss:// address, and a subprotocol if your server needs one.
- Connect, type a message, and send it.
- Watch the log of sent and received messages, and the close code when the connection ends.
Privacy & limitations
Connections go straight from your browser to your server; this site does not see the messages.
Related tools
Frequently asked questions
Why can I not connect to ws:// addresses?
This page is loaded over HTTPS, and browsers only allow secure wss:// connections from secure pages, except to localhost, which counts as secure.
What do the close codes mean?
1000 is a normal close, 1001 means the server or page is going away, 1006 means the connection dropped without a close message, and 1008 or 1011 mean the server refused or failed.
Why does the connection fail with no reason?
Browsers hide the details of failed connections for security. Check the address, that the server accepts connections from other origins, and the server's own logs.
Free tool · runs in your browser · no account required