WebSocket Tester
Test ws:// and wss:// connections and Server-Sent Events in real-time — free online client
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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 arrive in real time. Because the connection is opened from your own browser, what you see here is what your application would see: the same handshake, the same TLS behaviour, the same close codes. That makes it a fast way to answer the question that usually blocks you, which is whether the server is actually accepting connections at all, or whether the problem is in your client code. Server-Sent Events are supported alongside WebSocket, so a plain event stream and a full duplex socket can be debugged from the same place without installing a desktop client.
Key Features
- Connect to any WebSocket URL (ws:// and wss://) straight from the browser
- Check that a wss:// endpoint completes its TLS handshake and stays open
- Send custom text or JSON messages and view every frame with a timestamp
- Read the close code and reason when a connection drops, instead of guessing
- Server-Sent Events (SSE) testing alongside WebSocket debugging
- Auto-reconnect with live connection status monitoring
- Message history with search and filtering
- Works with local servers at ws://localhost during development
- Free, with no sign-up and no desktop client to install
Common Use Cases
- Checking whether a wss:// endpoint is reachable before blaming your client code
- Verifying a new WebSocket API before wiring up the frontend
- Debugging dropped connections and handshake failures by reading the close code
- Confirming a reverse proxy or load balancer is forwarding the Upgrade header
- Testing wss:// TLS endpoints in staging and production
- Inspecting message payloads from a real-time feed
- Monitoring a Server-Sent Events stream from an API
Frequently Asked Questions
How do I check a wss connection?
Paste the wss:// URL into the tester and click Connect. If the socket opens, the endpoint is reachable, the TLS certificate is valid, and the server completed the WebSocket upgrade — which rules out the three things that most often break a wss connection. If it fails, the close code and reason tell you which of those steps did not happen.
How do I test a WebSocket connection online?
Enter your WebSocket URL (ws:// or wss://), click Connect, and send a message. The log shows every frame in both directions with a timestamp, so you can confirm the server is responding and see exactly what it sent back.
Why does my WebSocket connection fail immediately?
The usual causes are a reverse proxy that is not forwarding the Upgrade and Connection headers, an invalid or self-signed TLS certificate on a wss:// endpoint, an origin check rejecting the request, or the server simply not listening on that path. The close code shown when the socket ends narrows it down quickly.
What is the difference between ws:// and wss://?
ws:// is an unencrypted WebSocket connection, the equivalent of HTTP. wss:// is a WebSocket over TLS, the equivalent of HTTPS. Use wss:// in production: as well as protecting data in transit, it is far less likely to be broken by intermediate proxies, and a page served over HTTPS is not allowed to open a plain ws:// connection at all.
Can I test a local WebSocket server?
Yes. The tester can connect to ws://localhost or ws://127.0.0.1, which is useful while developing a WebSocket server on your own machine. The connection is made by your browser, so it reaches your local server directly.
What are Server-Sent Events, and how do they differ from WebSocket?
Server-Sent Events are a one-way stream from server to browser over ordinary HTTP, with automatic reconnection built in. WebSocket is a two-way channel. If your clients only need to receive updates and never send them, SSE is simpler to operate — and this tool tests both.