VioLens

VioLens is a web debugging proxy. While it runs, it becomes the system proxy, and every request your browsers and apps make appears in a list, with HTTPS decrypted and compressed bodies decoded. It's free for personal and commercial use under the MIT licence, and runs on Windows 10/11 and Apple silicon Macs.

You can:

• Inspect requests and responses: headers, raw text, JSON, form data, cookies, images, hex and WebSocket messages
• See where time goes, with a waterfall of DNS, connection, TLS, server wait and download for every request
• Pause a request or response with a breakpoint, edit it, and let it continue
• Answer requests locally with AutoResponder rules: serve a file, redirect, add a delay or return an error
• Write or edit requests in the Composer and resend them, or replay a captured request
• Search inside bodies, compare two sessions side by side, and decode Base64, URL encoding and JWTs
• Capture traffic from phones and other devices, and work through corporate proxies, including PAC scripts and proxy sign-in
• Open and save SAZ and HAR files

If you're coming from Fiddler Classic, VioLens keeps the familiar workflow: SAZ files, FiddlerScript rules (OnBeforeRequest, OnBeforeResponse), QuickExec commands, breakpoints and AutoResponder all work the same way, and Fiddler extensions can be rebuilt from source for it. The proxy engine is also published on NuGet (Violens.ProxyCore), so developers can build their own tools on it.