What is the difference between ws:// and wss:// in the context of this tool?

The 'ws://' prefix denotes a plain WebSocket connection, which transmits data in cleartext and is susceptible to interception. 'wss://' stands for WebSocket Secure, which wraps the connection in a TLS/SSL layer, providing encryption and data integrity. In production environments, wss:// is mandatory to prevent security vulnerabilities and to avoid being blocked by browsers that enforce secure contexts (HTTPS).

Why does my WebSocket connection keep closing immediately after connecting?

Immediate closures are typically caused by a failed handshake or a server-side timeout. Common reasons include missing required authentication headers, a mismatch in the expected sub-protocol, or the server rejecting the origin of the request. Check the browser's network tab for a 401 Unauthorized or 403 Forbidden status code during the initial HTTP Upgrade request to pinpoint the issue.

Can this tool be used to test binary data or only text-based JSON?

The tool supports both text and binary frames. While most developers use it for JSON strings, you can toggle the data type to binary to send and receive ArrayBuffers or Blobs. This is essential for protocols that use Protobuf or MessagePack to reduce bandwidth overhead, allowing you to verify that the server correctly deserializes binary payloads.

How does the tool handle custom headers during the handshake?

The tool allows you to define key-value pairs that are injected into the initial HTTP GET request used to establish the WebSocket connection. This is critical for testing protected endpoints where the server requires an 'Authorization' header or a specific 'X-API-Key'. Without this capability, you would be unable to test any authenticated real-time services.

What are WebSocket 'frames' and why should I monitor them?

WebSockets break data into smaller units called frames. Monitoring individual frames allows you to see exactly how the server fragments large messages and how it handles control frames, such as Pings and Pongs. This level of granularity is vital for debugging network congestion issues or identifying why a specific large payload is causing the connection to drop.

Does the tool support sub-protocols like SOAP or MQTT over WebSockets?

Yes, by specifying the sub-protocol in the connection settings, the tool requests the server to communicate using a specific dialect. If the server agrees to the sub-protocol (e.g., 'v1.json' or 'mqtt'), the connection is established. This ensures that both the client and server are aligned on the message format and behavioral expectations of the session.

WebSocket Client Connection Tester

WebSocket Tester Online — Free Browser-Based WebSocket Client

A WebSocket tester lets you connect to any WebSocket server (ws:// or wss://) directly from your browser, send messages, and inspect server responses in real-time. No software installation required — this free online WebSocket client runs entirely in the browser. Use it to debug chat applications, live data feeds, real-time dashboards, financial ticker streams, IoT sensors, and WebSocket API endpoints.

How to Test a WebSocket Connection Online

Enter your WebSocket server URL (e.g., wss://echo.websocket.org) in the connection bar.
Click Connect. The status badge turns green when the connection is established.
Type a text or JSON message and press Enter or click Send.
Sent messages appear in blue on the right; received messages appear in grey on the left.
System events (connect, disconnect, errors) appear in yellow in the center.
Click Disconnect to close the connection cleanly.

Public WebSocket Echo Servers for Testing

Use these free public echo servers to verify your WebSocket client setup — they echo back every message you send:

wss://echo.websocket.org — Classic echo server by websocket.org
wss://ws.postman-echo.com/raw — Postman's public WebSocket echo endpoint
ws://localhost:PORT — Your own local development server

ws:// vs wss:// WebSocket Protocol

ws:// is the unencrypted WebSocket protocol (like HTTP). wss:// is the TLS-encrypted version (like HTTPS). Because this WebSocket tester runs over HTTPS, browsers block ws:// connections to external servers due to mixed-content security policy. Always use wss:// for production servers. Local ws://localhost connections still work fine because they are same-machine connections.

WebSocket ReadyState Values

The WebSocket.readyState property shows the current connection state:

0 (CONNECTING) — Connection is being established
1 (OPEN) — Connection is open and ready to send/receive messages
2 (CLOSING) — Connection is being closed
3 (CLOSED) — Connection is closed or could not be opened

Common WebSocket Error Codes

1000: Normal closure — connection closed cleanly and intentionally
1001: Going away — server is shutting down or browser is navigating away
1006: Abnormal closure — connection dropped unexpectedly (CORS issue, server down, or ws:// blocked from HTTPS)
1011: Server error — internal server error caused the connection to fail
1015: TLS handshake failure — certificate or TLS issue on wss://

Frequently Asked Questions

How do I test a WebSocket connection online?

Enter your WebSocket URL (ws:// or wss://) in this free online WebSocket tester and click Connect. Once the status turns green, send messages and see real-time server responses. No installation, no account, no software needed.

What is a WebSocket connection tester?

A WebSocket connection tester is a browser-based client that lets you establish a persistent WebSocket connection to any server, send messages, and inspect responses — useful for debugging WebSocket APIs, real-time apps, and verifying endpoint behavior without writing code.

Why does my WebSocket connection fail with error 1006?

Error 1006 (abnormal closure) means the connection dropped unexpectedly. Common causes: server rejected the connection (CORS or auth issue), wrong URL, server is down, or ws:// blocked from an HTTPS page.

Can I test a local WebSocket server with this tool?

Yes. ws://localhost:PORT or ws://127.0.0.1:PORT connections work fine from a browser. For local HTTPS environments, some browsers may restrict ws:// — use wss:// with a self-signed certificate.

Does this WebSocket client support sending JSON?

Yes. Type any JSON payload in the message field and click Send. Example: {"type":"subscribe","channel":"prices"}. Server responses appear in the message log with timestamps.

What is the difference between ws:// and wss://?

ws:// is unencrypted WebSocket (like HTTP). wss:// is encrypted WebSocket over TLS (like HTTPS). Use wss:// for all production servers. Browsers running on HTTPS pages block ws:// connections to external hosts due to mixed-content security policy.

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WebSocket Client Connection Tester – DataMorph