Once you’ve installed the built-in sniffer, just activate it by Shift+F2 or Tools -> WebDeveloper -> HTTPFox. The plugin interface is quite simple, having all the features accessible at once:
The extension gives the common set of HTTP sniffed data:
- Request and response headers
- String parameters
- POST data
- Content body
The timeline is not present, but the sniffer accomplishes the most needed sniffing tasks, results being subject for simple filtering.