Open-source alternatives to Fiddler

Cross-platform HTTP debugging proxy. — HTTP, HTTP2, HTTPS, Websocket debugging proxy

↔ alternative to Charles、Fiddler

Mobile HTTP capture and network diagnostic tool — AndroidHttpCapture网络诊断工具 是一款Android手机抓包软件 主要功能包括：手机端抓包、PING/DNS/TraceRoute诊断、抓包HAR数据上传分享。你也可以看成是Android版的"Fiddler" \(^o^)/~

↔ alternative to Fiddler

An all-in-one protocol analysis toolkit with browser capture and AI. — 全能协议分析工具：浏览器抓包 + MITM 代理 + 指纹伪装 + AI 分析 + MCP Server 无缝对接 AI Agent/IDE | All-in-one protocol analysis toolkit — built-in browser capture, MITM proxy, JS hooks, fingerprint spoofing, AI analysis & MCP server for agent integration

↔ alternative to Charles Proxy、Fiddler

Debug and inspect gRPC traffic like Fiddler. — A suite of gRPC debugging tools. Like Fiddler/Charles but for gRPC.

↔ alternative to Fiddler、Charles Proxy

WebSocket traffic control and proxy — Complete WebSocket Traffic Control with advanced proxy, simulation, and blocking capabilities

↔ alternative to Charles Proxy、Fiddler、Proxyman