Open-source native macOS HTTP debugging proxy — intercept HTTPS, inspect APIs, mock responses, debug WebSocket & GraphQL. Community-driven. For developers, by developers.

MCP server enabling agents to debug HTTP requests better (using powhttp)

A Windows HTTP(S) debugging proxy built from scratch in C# and .NET 10. Capture, inspect, filter, replay, and compose HTTP/1.1, HTTP/2, and upstream HTTP/3 traffic with TLS decryption and rich body views.

Cross-platform HTTP/HTTPS/WebSocket debugging proxy GUI powered by whistle, built with Electron and React.

Debugging proxy made for web developers

Dev Proxy is a Microsoft command-line tool for simulating, testing, and debugging API interactions during development.

Scripts to help with debugging apps (especially iOS apps) using OWAZP ZAP

Light weight HTTP Proxy with web-ui

Whistle is a cross-platform HTTP, HTTPS, HTTP/2, WebSocket, and TCP debugging proxy built on Node.js. It enables developers to inspect, intercept, modify, and replay network traffic through a rule-based configuration system with a built-in web UI.

Proxyman is a modern, native macOS app for HTTP/HTTPS debugging proxy with advanced features for API development and testing.