debugging-proxy

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)

Free, open-source Fiddler Classic alternative for Windows. Capture, inspect, filter, replay, compose and mock HTTP/HTTPS traffic with TLS decryption, HTTP/2, HTTP/3 and SAZ support.

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

Debugging proxy made for web developers

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

Dev Proxy — independent third-party profile of a public API surface, by API Evangelist. Dev Proxy is a Microsoft command-line tool for simulating, testing, and debugging API interactions during development.

Whistle — independent third-party profile of a public API surface, by API Evangelist. 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 — independent third-party profile of a public API surface, by API Evangelist. Proxyman is a modern, native macOS app for HTTP/HTTPS debugging proxy with advanced features for API development and testing.