What is Websocket Tester
The WebSocket Tester is a client-side tool that establishes WebSocket connections to specified servers and provides an interactive interface for sending and receiving messages. It features a URL input field (defaulting to wss://echo.websocket.org), a Connect button, a Send button (which sends the text "ping"), a Close button, and a scrollable log panel that displays all connection events: successful connection, received messages, disconnection with close code, and errors. The tool creates a new WebSocket instance with the specified URL, attaches event handlers for open, message, close, and error events, and displays each event in the log with a status indicator (checkmark for success, X for errors/closure). The Send button sends a predefined "ping" message — this is a simple test to verify the server responds. The Close button gracefully closes the connection with the default close code. This tool is essential for debugging WebSocket-based applications, testing server connectivity, and verifying that WebSocket endpoints are reachable and responding.
How to Use Websocket Tester
- Step 1: Enter a WebSocket URL in the input field (e.g., wss://echo.websocket.org or ws://localhost:8080). The URL must start with ws:// or wss://.
- Step 2: Click Connect. The tool creates a WebSocket connection and logs the result. A checkmark entry indicates successful connection; an X indicates failure.
- Step 3: Once connected, click Send to transmit a test message ("ping"). If the server echoes responses, they will appear in the log prefixed with a left arrow.
- Step 4: To end the session, click Close. The tool logs the close code and the connection is terminated. You can reconnect by clicking Connect again.
Why Use Websocket Tester
WebSocket connections are notoriously difficult to debug because they operate outside the normal HTTP request/response cycle. When a WebSocket fails to connect, the issue could be the URL, authentication, network policy, server configuration, or protocol mismatch. The WebSocket Tester isolates the connection itself — by testing with a simple echo server first, you can confirm that WebSocket connectivity works in general before debugging your specific application's WebSocket logic. The log panel provides immediate visibility into the connection lifecycle, which is especially valuable for diagnosing connection drops, unexpected close codes, and message delivery failures.
Privacy & Security
This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.
Frequently Asked Questions
Why does the echo.websocket.org server not respond?
<p>The echo.websocket.org service may be unavailable or deprecated. Try using a local WebSocket server or another echo service for testing. The tool works with any WebSocket endpoint.</p>
Can I send custom messages?
<p>The current Send button sends a hardcoded "ping" message. For custom messages, you would need to modify the tool to accept user input for the message body.</p>
Does it support binary messages?
<p>The tool sends and receives text messages only. Binary WebSocket frames (ArrayBuffer, Blob) are not currently handled in the log display.</p>
Why does the connection fail immediately?
<p>Common causes: the server is not running, the URL is wrong (check ws:// vs wss://), a firewall is blocking the connection, or the server requires specific subprotocol headers that the tool does not send.</p>
Can I test authentication-protected WebSockets?
<p>Not directly — the tool does not support custom headers or authentication tokens in the WebSocket handshake. For authenticated connections, you would need to extend the tool or use a library like Socket.IO.</p>