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WebSocket monitor is a Firefox extension that can be used to monitor WebSocket connections in Firefox. It allows to inspect all data sent and received.

• WebSocket monitor requires a platform support that isn't part of any standard release channel yet. You need to either manually apply patches from bug 1203802 and build your own Firefox or download provided try builds, see releases.

Features

• Frame Inspection
• Frame Filtering
• Summary Data
• Themes
• Socket.IO Support
• Table and List Perspectives

Are you missing a feature? Create a report.

Start With WebSocket Monitor

When you open Firefox developer Toolbox (press F12) you should see a new Web Sockets panel. Select the panel and open e.g. this simple test page. Initiate web socket connection on the page and see list of frames appearing in the panel.

Frame Inspection

It's possible to inspect all sent and received WS frames. The extension visualizes frame meta data as well as the payload.

• Select a frame in the list of frames
• All details are displayed on the right side

Frame Filtering

The extension allows simple filtering of frames. It's possible to filter the list of frames using a keyword. Only frames that contains the keyword in the payload are displayed.

Summary Data

There is a quick summary displayed at the bottom of the frame list.

• Number of frames in the list
• Total size of transferred payload
• Total time since the first frame

Themes

Both built-in DevTools themes (Dark and Light) are supported.

Socket.IO Support

Table and List Perspectives