hello, i think that extension is just recording/logging the headers as you are browsing along in the browser - so i think you just have to open httpfox and enter the address you want to inspect in the firefox address bar. if you have more detailed questions about extensions, please contact the developers of the extension themselves or use the support channels they provide, since they can give you far more detailed guidance. eidt: i think firefox also offers the same functionality inbuilt in the net section of the webconsole in tools > web-developer, [https://developer.mozilla.org/en/Using_the_Web_Console]