WebSocket & SSE Debugger
Test WebSocket and Server-Sent Events connections in real-time
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Test WebSocket Connections Online
A free online WebSocket tester and client — connect to any ws:// or wss:// endpoint, send text or JSON messages, and watch incoming frames in real time. It also supports Server-Sent Events (SSE), so you can debug both WebSocket APIs and event streams from one place without installing a desktop client.
Key Features
- Connect to any WebSocket URL (ws:// and wss://) straight from the browser
- Send custom text or JSON messages and view all frames with timestamps
- Server-Sent Events (SSE) testing alongside WebSocket debugging
- Auto-reconnect with connection status monitoring
- Message history with search and filtering
- Works with local servers at ws://localhost for development
- Free WebSocket test tool with no sign-up required
Common Use Cases
- Verifying a new WebSocket API before wiring up the frontend
- Debugging dropped connections and handshake failures
- Testing wss:// TLS endpoints in staging and production
- Inspecting message payloads from a real-time feed
- Checking a local WebSocket server during development
- Monitoring Server-Sent Events streams from an API
Frequently Asked Questions
How do I test a WebSocket connection online?
Enter your WebSocket URL (ws:// or wss://), click Connect, and start sending and receiving messages. The tool shows the full message log with timestamps.
How do I debug a WebSocket API?
Connect to any WebSocket server, send custom text or JSON messages, and view all incoming frames in real time. You can also add custom headers for authenticated WebSocket connections.
What is the difference between ws:// and wss://?
ws:// is an unencrypted WebSocket connection, similar to HTTP. wss:// is an encrypted WebSocket connection over TLS, similar to HTTPS. Always use wss:// in production to protect data in transit.
Can I test a local WebSocket server online?
Yes. The tester can connect to local WebSocket servers at ws://localhost or ws://127.0.0.1. This is useful for testing WebSocket servers running on your development machine.