How do I test a WebSocket connection from my browser?

Select WebSocket, enter a ws:// or wss:// URL and press Connect. Once the status shows Connected, type a message and press Send. Sent and received frames appear in Messages with timestamps.

Can I test Server-Sent Events as well?

Yes. Choose Server-Sent Events and enter an http:// or https:// endpoint. SSE is receive-only here. For named events, list their names in SSE event names, comma-separated, before connecting.

Why do I get a WebSocket error when connecting?

The tool suggests checking that the URL starts with ws:// or wss:// and that the server allows connections from browsers. The connection goes straight from your browser to that server.

Can I add custom headers or an auth token to the connection?

No. The tool opens a standard browser WebSocket to the URL you type and has no header fields. Anything else must be passed in the URL itself.

How do I keep the connection alive and save the message log?

Turn on Auto-ping every and set the seconds; it sends the text ping while connected. The log keeps the latest 200 entries, and Export downloads them as websocket-log.txt.

Yes. Every tool is free to use, with no account and no credit card. The work runs on your device rather than on our servers, which is what keeps it free to run.

Does it work on mobile?

Yes. It runs in current mobile browsers on iOS and Android, with nothing to install.

🔌

Free WebSocket / SSE Tester

Connect to a WebSocket (ws/wss) or Server-Sent Events endpoint from your browser, send messages, and watch the live message log with timestamps. A fast way to debug a realtime API — nothing is proxied through us.

Runs in your browserNo sign-up, no pop-upsNo login requiredFree forever

WebSocket URL (ws:// or wss://)

Disconnected

Messages

Pretty JSON

No messages yet. Connect to begin.

Auto-ping everys

Connections are made directly from your browser to the endpoint you enter — LibraTool is never in the middle. Public test servers like wss://echo.websocket.org echo back whatever you send. Press the up arrow in the message box to recall previously sent messages.

How It Works

Connects from your browser to a WebSocket or Server-Sent Events endpoint, lets you send messages, and shows the live message log with timestamps — a quick way to debug a realtime API.

1
Pick a protocol and URL
WebSocket (ws:// or wss://) or SSE (http/https). A public echo server is pre-filled so you can try it immediately.
2
Connect
The browser opens the connection directly to your endpoint. A status dot shows connecting / open / closed.
3
Send and watch
For WebSockets, type a message and send it; incoming and outgoing frames are logged with timestamps. For SSE, events stream in as the server pushes them.

The connection is made directly from your browser to the endpoint you choose. LibraTool is never in the middle.

Related Tools

🔍

Regex Tester

Test regular expressions against text in real time. See highlighted matches, groups, and match details.

Try it

📊

Decibel Meter

Measure sound level from your microphone in real time, with min/max/average and a 60-second scrolling history — right in your browser.

Try it

⌨️

Keyboard Tester

Test every key on your keyboard: each key lights up as you press it, with its key and code values, a key log, and a warning if a key stays down.

Try it

Free WebSocket / SSE Tester

How It Works

Related Tools

Regex Tester

Decibel Meter

Keyboard Tester

Frequently Asked Questions