HttpWatch : An HTTP Viewer and HTTP Sniffer for IE and Firefox
Wireshark : Wireshark is the world's foremost network protocol analyzer. It lets you see what's happening on your network at a microscopic level. It is the de fac...
Smocker : Smocker (server mock) is a simple and efficient HTTP mock server. Smocker exposes a configuration user interface and a configuration api to register n...
Mockbin : Mockbin allows you to generate custom endpoints to test, mock, and track HTTP requests & responses between libraries, sockets and APIs.
namebench : namebench hunts down the fastest DNS servers available for your computer to use. namebench runs a fair and thorough benchmark using your web browser h...