WebSocket Tester
LiveConnect to WebSocket endpoints, send/receive messages, and inspect real-time traffic.
No messages yet. Connect to start.
Understanding WebSocket Protocol
WebSocket is a communication protocol that provides full-duplex, persistent connections between a client and server over a single TCP connection. Unlike HTTP's request-response model, WebSocket allows both sides to send messages at any time without polling, making it ideal for real-time applications — live chat, multiplayer games, collaborative editing, stock tickers, IoT sensor feeds, and push notifications. WebSocket connections begin as HTTP upgrades (status 101) and then switch to the WebSocket frame protocol for efficient bidirectional data transfer.
The WebSocket Tester lets you connect to any WebSocket server, send text or JSON messages, and view incoming messages in real-time. Includes connection status indicators, message history with timestamps, and the ability to send custom headers. Perfect for debugging WebSocket APIs, chat servers, and real-time data feeds.
The Devkitr WebSocket Tester establishes a live WebSocket connection to any endpoint, allowing you to send messages, receive responses, and monitor the connection lifecycle in real time. Enter a ws:// or wss:// URL, optionally add subprotocols or custom headers, connect, and interact with the server through a message log that displays both sent and received frames with timestamps.
In a typical development workflow, WebSocket Tester becomes valuable whenever you need to connect to websocket endpoints, send/receive messages, and inspect real-time traffic. Whether you are working on a personal side project, maintaining production applications for a company, or collaborating with a distributed team across time zones, having a reliable browser-based inspection tool eliminates the need to install desktop software, write one-off scripts, or send data to third-party services that may log or retain your information. Since WebSocket Tester processes everything locally on your device, your data stays private and your workflow stays uninterrupted — open a browser tab, paste your input, get your result.
Key Features
Live Connection Dashboard
Displays real-time connection status (connecting, open, closing, closed) with color-coded indicators and automatic reconnection detection.
Message Log with Timestamps
Every sent and received message is logged with precise timestamps, message size, and direction indicators for analyzing communication patterns.
JSON Message Formatting
Automatically detects and formats JSON messages in the log, making structured WebSocket payloads readable without manual formatting.
Custom Subprotocol Support
Specify subprotocols during the WebSocket handshake for testing endpoints that require protocol negotiation like STOMP or MQTT over WebSocket.
How to Use WebSocket Tester
Enter the WebSocket URL
Type the endpoint address starting with ws:// (unencrypted) or wss:// (encrypted). Include any path or query parameters the server expects.
Establish the Connection
Click connect to initiate the WebSocket handshake. The tool displays the connection status and any handshake headers exchanged.
Send and Receive Messages
Type messages in the input field and send them to the server. Incoming messages appear automatically in the log with timestamps.
Analyze the Communication
Review the message log to verify protocol behavior, response timing, and message content. Disconnect when testing is complete.
Use Cases
Developing Real-Time Features
Test WebSocket endpoints for chat applications, live notifications, or collaborative features by sending messages and verifying server broadcasts.
Debugging Connection Issues
Diagnose WebSocket problems like failed handshakes, unexpected disconnections, or missing messages by monitoring the full connection lifecycle.
Verifying Message Formats
Send various JSON payloads to test server-side message parsing and validate that responses conform to the expected schema.
Load Testing Preparation
Manually test WebSocket behavior under different message frequencies and payload sizes before running automated load tests.
Pro Tips
Always use wss:// (WebSocket Secure) for production endpoints — browsers block mixed content, and unencrypted WebSocket fails on HTTPS pages.
Test reconnection logic by intentionally closing and reopening connections — real-world WebSocket apps must handle network interruptions gracefully.
Monitor message size — WebSocket frames have a default max size of 64KB in many server implementations. Larger messages may need fragmentation.
Use ping/pong frames to test keep-alive behavior. Many servers close idle connections after 30-60 seconds without heartbeat messages.
Common Pitfalls
Not handling connection close events in client code
Fix: WebSocket connections can close unexpectedly due to network issues, server restarts, or timeouts. Implement onclose handlers with automatic reconnection and exponential backoff.
Sending messages before the connection is fully established
Fix: Wait for the onopen event before sending messages. Sending on a connecting socket throws errors or silently drops messages.
Ignoring WebSocket close codes
Fix: Close codes indicate why a connection ended — 1000 is normal, 1006 is abnormal, 1008 is policy violation. Handle each code appropriately in your application.
Frequently Asked Questions
QCan I connect to wss:// secure endpoints?
Yes. Both ws:// and wss:// protocols are supported. Secure connections work as long as the server has a valid SSL certificate.
QDoes it support custom headers?
Browser WebSocket API has limited header support. You can send authentication tokens as query parameters or in the first message payload.
QIs there a message size limit?
There is no client-side limit. The server may impose its own message size restrictions.
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