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.

Free, open-source HTTP, HTTPS and WebSocket debugging proxy for Windows and macOS. Rust core + Electron UI. Alternative to Charles, Proxyman and Fiddler.

A modern Fiddler Classic alternative for macOS. A Fiddler clone for Mac: capture and inspect HTTP/HTTPS traffic, and replay HAR files with an AutoResponder.

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

Local HTTP/HTTPS debugging proxy that understands LLM API traffic (OpenAI, Anthropic, Gemini, Copilot): token usage, cost, streaming reconstruction. Sessions saved as plain JSON so coding agents can read them.

Debugging proxy made for web developers

Claude Code mod: an HTTPS debugging proxy (Proxyman/Charles alternative). Intercepts and decrypts traffic from your browser, iOS Simulator, iPhone and Android, lists and filters every request, and lets Claude read them.

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.