Apps similar to Sniffy include Fiddler, which has a free version. Other options are mitmproxy, HTTP Toolkit, Charles and VioLens. In total there are six HTTP(S) Debuggers like Sniffy for Windows, Mac, Linux, iPhone and Android.
Web Debugging Proxy that logs all HTTP(S) traffic for comprehensive analysis. It allows manipulation of traffic, supports scripting, and extends with .NET. Debugs virtually any application, implementing man-in-the-middle interception with self-signed certificates. Freeware, ideal for developers.
United States
mitmproxy is an SSL-capable man-in-the-middle proxy for HTTP. It provides a console interface that allows traffic flows to be inspected and edited on the fly. It also features mitmdump, a commandline tool that provides a tcpdump-like interface for saving, viewing and...
HTTP Toolkit is a beautiful, cross-platform & open-source HTTP(S) debugging proxy, analyzer & client, with built-in support for modern tools and automatic interception for clients from Docker to Android to iOS.
Spain
EU
Charles is an HTTP proxy / HTTP monitor / Reverse Proxy that enables a developer to view all of the HTTP and SSL / HTTPS traffic between their machine and the Internet. This includes requests, responses and the HTTP headers (which contain the cookies and caching information).
New Zealand
An MIT-licensed web debugging proxy for Windows and Apple silicon Macs that decrypts HTTPS traffic, decodes compressed bodies, and captures app requests. Inspect and edit sessions, view timing waterfalls, mock responses, replay traffic, and open SAZ or HAR files.
Reqable is a modern cross-platform project, designed for API development, testing, and debugging. Reqable fully supports HTTP1 and HTTP2 and partially supports HTTP3(QUIC).
