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.

HTTP(S) debugging proxy for macOS, Windows and Linux: capture, inspect, mock, break and replay traffic, diagnose what slows it down, and see what AI agents like Claude Code and Codex do — LLM calls, tokens and costs, MCP tool calls, prompt cache. A modern Fiddler alternative.

Wirepane: an HTTPS debugging proxy inside Claude Code (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.

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.

Intercepting forward proxy library for Go that supports HTTP/1.1, HTTP/2, HTTP/3, gRPC, WebSocket, TCP, QUIC and UDP, in explicit, transparent and SOCKS5 modes.

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.

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.

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.