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A Windows-native HTTP/HTTPS debugging proxy with an AI-powered assistant, built with Electron.

⚠️ This is a personal/experimental project. If you need a mature, production-ready HTTP debugging proxy, go check out Proxyman — it's excellent and was the direct inspiration for this project. ProxyBoy exists because I wanted a Windows-native alternative with agentic AI capabilities baked in, and I wanted to learn by building one.

What is this?

ProxyBoy is a man-in-the-middle (MITM) HTTP/HTTPS proxy that captures, inspects, and modifies network traffic — similar to Charles Proxy, Fiddler, or Proxyman. What makes it different is the embedded AI assistant powered by the GitHub Copilot SDK, which can analyze traffic, create rules, and help debug network issues conversationally.

Features

Traffic Capture — Intercept HTTP and HTTPS traffic with automatic SSL certificate generation

Request/Response Inspector — View headers, bodies (JSON, HTML, XML, images), timing, and metadata

GraphQL Awareness — Detect GraphQL operations, show operation names, and filter traffic by operation

Protobuf / gRPC Decoding — Decode protobuf payloads in the detail view with .proto files and fall back to raw field inspection when schemas are missing

No Cache Toggle — Strip cache validators and return Cache-Control: no-store to force fresh responses

Network Throttling — Simulate slower links with preset or custom upload, download, and latency profiles

Request Composer — Build a request from scratch, send it through ProxyBoy, and inspect the captured result inline

Upstream Proxy Chaining — Forward traffic through HTTP or SOCKS5 upstream proxies with bypass patterns and secure credential storage

Cookie Inspector — Parse request cookies and Set-Cookie headers into a structured, searchable view

AI Assistant — Chat panel powered by GitHub Copilot that can search traffic, analyze patterns, create rules, and export data

Breakpoint Rules — Pause requests/responses mid-flight, inspect them, then forward or drop

Map Local Rules — Serve local files instead of remote responses for mocking APIs

Map Remote Rules — Forward matching requests to a different upstream host without changing your client

Capture Rules — Switch between capture-all, allow-list, and block-list modes to control what gets recorded

System Proxy Integration — Toggle Windows system proxy on/off from the app

HAR Export/Import — Standard HAR format for sharing captures with other tools

Configurable Columns — Show/hide columns, sort by any field, timestamps

Body Search — Include request and response text bodies in traffic filtering when you need deeper search

WebSocket and SSE Inspection — Capture live WebSocket frames and Server-Sent Events in the traffic detail view

Script Rules — Run sandboxed JavaScript rules to rewrite requests and responses without leaving the app

Copy as cURL — Right-click any request to copy it as a cURL command

Keyboard Shortcuts — Fast access to proxy control, HAR import/export, filtering, and traffic actions

Theme Modes — Dark, Light, or System theme selection with live switching

Detachable AI Panel — Pop the assistant out into its own window

In Action

HAR Import + Image Preview + AI Session Analysis

Import a HAR file, preview images inline, and ask the AI assistant to break down what's in the capture.

Content Type Filtering + JSON Body Viewer

Filter traffic by content type (JSON, HTML, CSS, JS, images, etc.) and inspect formatted response bodies.

AI-Powered Request Analysis

Select any request and ask the AI to explain it — it calls tools like analyzeFlow to inspect headers, body, and context, then gives you a human-readable breakdown.

AI Assistant Tools

The embedded Copilot agent has access to these tools:

Tool Description

getRecentTraffic Fetch the latest captured flows

searchTraffic Search flows by URL, body, or headers

getErrorFlows Find all 4xx/5xx responses

getFlowDetails Deep-dive into a specific request

createBreakpointRule Create a breakpoint to pause matching traffic

createMapLocalRule Mock an API endpoint with a local file

exportHar Export captured traffic as HAR

controlProxy Start or stop the proxy engine

Tool execution can be auto-approved or require manual confirmation per-call.

Tech Stack

Electron + React + TypeScript

http-mitm-proxy — MITM proxy engine

@github/copilot-sdk — AI agent capabilities

sql.js — SQLite in-process for persistence

Tailwind CSS — Styling

react-virtuoso — Virtualized traffic list

Electron Forge — Build and packaging

Getting Started

Prerequisites

Windows 10/11

Node.js 20+

GitHub Copilot subscription (for the AI assistant — the proxy works without it)

Install & Run

git clone https://github.com/pjperez/proxyboy.git cd proxyboy npm install npm start

Build Installer

npm run build

Output goes to out/make/.

Usage

Start the proxy — Click the play button in the status bar or use the AI assistant

Route traffic — Either toggle "System Proxy" in settings, or manually configure your browser/app to use 127.0.0.1:9090

Inspect — Click any row to see request/response details

Create rules — Use the Breakpoints, Map Local, or Map Remote views, or ask the AI assistant

AI Assistant — Click the robot icon in the sidebar or press Ctrl+Shift+A

SSL/HTTPS

To inspect HTTPS traffic, you'll need to trust ProxyBoy's root CA certificate:

Go to Settings → Install Certificate

This installs a local root CA into the Windows certificate store

Restart your browser after installing

The certificate is generated locally and stored in your user profile. It never leaves your machine.

Troubleshooting SSL

If a request fails immediately after TLS setup and ProxyBoy tags it as ssl-pinning-suspected, the target app is probably rejecting the ProxyBoy MITM certificate instead of accepting your locally trusted CA.

Common approaches:

Android debug builds — Use a debug-only network security config or a test build that trusts user-installed CAs.

iOS simulators — Prefer development builds with pinning disabled, or use instrumentation tools in local test environments.

Desktop apps / Electron apps — Check for developer flags, debug certificates, or test-only trust overrides before trying to intercept production builds.

ProxyBoy can only point out the likely cause. Certificate pinning bypasses are app-specific, and the safest path is usually a debug/test build with relaxed certificate validation.

Project Structure

src/ ├── main/ # Electron main process │ ├── proxy/ # MITM proxy engine, interceptor, certificate manager │ ├── agent/ # Copilot SDK client, tools, prompts │ ├── ipc/ # IPC handlers between main ↔ renderer │ ├── storage/ # SQLite database, queries │ └── utils/ # Windows proxy settings, HAR export ├── renderer/ # React UI │ ├── components/ # Traffic list, detail view, agent panel, rules editors │ ├── stores/ # Zustand state management │ └── utils/ # cURL generation, helpers └── shared/ # Types, constants shared between main & renderer

Known Limitations

Windows only — System proxy integration uses Windows registry; the rest could theoretically work cross-platform

No request/response editing in breakpoints — You can inspect and forward/drop, but not modify (yet)

SSL inspection quirks — Some sites with certificate pinning or HSTS preload may not work through the proxy

Cloudflare challenges — Sites behind Cloudflare browser challenges will typically fail through any MITM proxy

Very limited automated tests — There is a small test foothold now, but coverage is still far from production-ready 🙃

Acknowledgments

Proxyman — The primary inspiration. Seriously, go use Proxyman if you want a polished, reliable proxy tool. It's great.

Charles Proxy and Fiddler — Other excellent tools in this space

GitHub Copilot — Powers the AI assistant, and also helped build this entire app

License

MIT — Do whatever you want with it.

About

Windows HTTP/HTTPS debugging proxy with AI-powered analysis. Inspired by Proxyman.

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ProxyBoy v1.5.0

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Mar 23, 2026

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