what is a fiddler
About (from Telerik). Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet. Fiddler allows you to inspect traffic, set breakpoints, and fiddle with incoming or outgoing data.bout (from Telerik). Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet. Fiddler allows you to inspect traffic, set breakpoints, and fiddle with incoming or outgoing data.