PROTOCOLS
WebSocket
Real-time two-way communication testing — connect to WebSocket endpoints, send and receive messages, and inspect traffic with direction indicators and timestamps.
Connecting
WebSocket mode activates automatically when the URL starts with ws:// or wss://.
Protocol selector auto-switches to WebSocket mode
Send button becomes Connect / Disconnect
Method selector is hidden (WebSocket doesn't use HTTP methods)
Available tabs: Params, Headers, Auth only (no body, tests, scripts)
Connection handshake includes custom headers and auth
Connection state shown in the response area
Example URLs:
wss://echo.websocket.org
wss://ws.postman-echo.com/raw
ws://localhost:8080/wsMessage Composer
The message composer appears at the bottom of the WebSocket panel once connected.
Text input field for composing messages
Type selector: Text or JSON
Click Send (or press Enter) to send a message over the open connection
JSON mode pretty-prints and validates before sending
Messages can contain
{{variables}} (resolved before sending)Message Log
All messages are displayed in chronological order with direction indicators and timestamps.
↑
Sent Messages
Green arrow (↑) — messages you sent to the server
↓
Received Messages
Blue arrow (↓) — messages received from the server
Timestamps on each message
JSON messages auto pretty-printed
Direction filter: All / Sent / Received
Clear button to reset the log
Note: Messages are NOT persisted to history — they are ephemeral and exist only during the active connection. Cleared on disconnect.
Auth & Headers
Authentication and custom headers are injected into the WebSocket upgrade request (HTTP handshake).
All auth types supported: Basic, Bearer, API Key, OAuth 2.0, AWS SigV4, Digest
Custom headers injected into the upgrade request
Params tab adds query parameters to the
ws:// URLCurrent Limitations
| Feature | Status |
|---|---|
| Binary messages | Not yet supported (text frames only) |
| Ping/pong | Handled at protocol level, not exposed in UI |
| Message history | Not saved to disk — cleared on disconnect |
| Reconnect | No automatic reconnection — must click Connect again |
| Multiple connections | One connection per tab (cannot have multiple WS connections in same tab) |
| Client/bidirectional streaming | Use gRPC for those patterns |
| Request body tab | WebSocket doesn't have a request body concept |
Tips
Test with:
wss://echo.websocket.org (echoes messages back)Use JSON type for structured messages — easier to read in the log
Close tab to auto-disconnect (prevents leaked connections)
For GraphQL subscriptions over WS, use the GraphQL protocol instead (handles
graphql-transport-ws automatically)