NectoProxy

A powerful HTTP/HTTPS debugging proxy with a modern Web UI. A free, open-source alternative to Charles Proxy and Fiddler.

Intercept, inspect, modify, and replay HTTP/HTTPS traffic with real-time monitoring, traffic rules, breakpoints, and more.

Documentation: https://sitharaj88.github.io/nectoproxy/

Installation

npm install -g nectoproxy

Or run directly with npx:

npx nectoproxy start

Requirements: Node.js 20 or later.

Quick Start

# Start the proxy server and Web UI
nectoproxy start

# The proxy starts on port 8888, Web UI on port 8889
# Your browser will open automatically

Configure Your Browser/System

1. Set your HTTP proxy to localhost:8888
2. Install the CA certificate to inspect HTTPS traffic:

   nectoproxy cert --install

Features

Traffic Inspection

• HTTP/HTTPS Interception — MITM proxy with auto-generated per-domain SSL certificates
• Real-time Monitoring — Watch requests/responses stream in via WebSocket with virtualized list for thousands of entries
• Request/Response Details — Inspect headers, body (with syntax highlighting), timing, and TLS info
• WebSocket Support — Capture and inspect WebSocket frames (WS/WSS)

Traffic Control

• Rules Engine — 8 built-in actions:
  • Mock — Return custom responses without hitting the server
  • Block — Reject requests entirely
  • Modify Request — Add/remove headers, change query params, replace body
  • Modify Response — Change status, headers, or response body
  • Map Local — Serve files from your local filesystem
  • Map Remote — Redirect requests to a different URL
  • Delay — Add artificial latency with optional variance
  • Throttle — Limit bandwidth to simulate slow connections
• Breakpoints — Pause requests/responses for manual inspection and modification before forwarding
• Network Conditioning — Simulate various network profiles (3G, slow Wi-Fi, etc.) with bandwidth, latency, and packet loss controls

Analysis & Export

• HAR Import/Export — Standard HTTP Archive format for sharing and analysis
• Code Generation — Generate equivalent code in 7 languages: cURL, Python, Node.js, Go, PHP, Rust, and more
• Request Comparison — Diff two requests side-by-side
• Request Replay — Re-send captured requests and compare responses
• Dashboard — Visual analytics with traffic charts and statistics
• Security Scanning — Identify potential security issues in captured traffic

Developer Experience

• Modern Web UI — React dashboard with dark and light themes
• Keyboard Shortcuts — Navigate and control the proxy efficiently
• Command Palette — Quick access to all features
• Session Management — Organize traffic into named sessions
• Upstream Proxy — Chain through HTTP, HTTPS, SOCKS4, or SOCKS5 proxies
• Filtering — Filter traffic by method, status code, URL, host, and content type

CLI Reference

# Start the proxy
nectoproxy start [options]
  -p, --port <port>       Proxy port (default: 8888)
  -u, --ui-port <port>    Web UI port (default: 8889)
  --host <host>           Host to bind to (default: 0.0.0.0)
  --no-open               Don't auto-open browser

# Certificate management
nectoproxy cert --install       Show CA certificate installation instructions
nectoproxy cert --path          Print CA certificate file path
nectoproxy cert --clear-cache   Clear cached domain certificates

# Session management
nectoproxy sessions --list            List all sessions
nectoproxy sessions --create <name>   Create a new session
nectoproxy sessions --delete <id>     Delete a session

# Version
nectoproxy --version

Certificate Setup

To inspect HTTPS traffic, install the NectoProxy CA certificate in your browser/system:

macOS

sudo security add-trusted-cert -d -r trustRoot \
  -k /Library/Keychains/System.keychain \
  ~/.nectoproxy/certs/ca.pem

Windows (PowerShell as Administrator)

Import-Certificate -FilePath "$env:USERPROFILE\.nectoproxy\certs\ca.pem" `
  -CertStoreLocation Cert:\LocalMachine\Root

Linux (Ubuntu/Debian)

sudo cp ~/.nectoproxy/certs/ca.pem /usr/local/share/ca-certificates/nectoproxy-ca.crt
sudo update-ca-certificates

Firefox (all platforms)

1. Settings > Privacy & Security > Certificates > View Certificates
2. Authorities tab > Import > Select ~/.nectoproxy/certs/ca.pem
3. Check "Trust this CA to identify websites"

Comparison

| Feature | NectoProxy | Charles Proxy | Fiddler | mitmproxy | |---------|-----------|---------------|---------|-----------| | Price | Free & Open Source | $50 | Free* | Free & Open Source | | Web UI | Yes | No (native) | No (native) | Yes (mitmweb) | | HTTPS Interception | Yes | Yes | Yes | Yes | | WebSocket Inspection | Yes | Yes | Yes | Yes | | Rules/Rewriting | Yes (8 actions) | Yes | Yes | Yes (scripts) | | Breakpoints | Yes | Yes | Yes | Yes | | Network Throttling | Yes | Yes | Yes | No | | HAR Export | Yes | Yes | Yes | Yes | | Code Generation | Yes (7 languages) | No | No | No | | Request Comparison | Yes | No | No | No | | Cross-platform | Yes | Yes | Windows* | Yes |

*Fiddler Classic is Windows-only; Fiddler Everywhere is cross-platform but paid.

Architecture

nectoproxy/
├── apps/
│   ├── cli/          # CLI entry point (npm package)
│   └── web/          # React Web UI (bundled with CLI)
├── packages/
│   ├── certs/        # SSL/TLS certificate generation (node-forge)
│   ├── core/         # MITM proxy engine (net/tls/http)
│   ├── server/       # Express REST API + Socket.IO
│   ├── shared/       # TypeScript type definitions
│   └── storage/      # SQLite database (better-sqlite3 + Drizzle ORM)

Tech Stack

• Runtime: Node.js 20+, TypeScript
• Monorepo: pnpm workspaces + Turborepo
• Proxy: Native Node.js http/net/tls modules, node-forge for certificates
• Storage: better-sqlite3 + Drizzle ORM
• API: Express + Socket.IO
• UI: React 18 + Vite + TailwindCSS + Zustand + React Query

Development

# Clone the repository
git clone https://github.com/sitharaj88/nectoproxy.git
cd nectoproxy

# Install dependencies
pnpm install

# Build all packages
pnpm build

# Run in development mode (watch mode)
pnpm dev

# Run tests
pnpm test

Data Storage

All data is stored locally in ~/.nectoproxy/:

• ~/.nectoproxy/certs/ — CA and domain certificates
• ~/.nectoproxy/nectoproxy.db — SQLite database (sessions, traffic, rules, settings)

Author

Sitharaj Seenivasan

• Website: sitharaj.in
• LinkedIn: sitharaj08
• Buy Me a Coffee: sitharaj88

If you find NectoProxy useful, consider supporting the project:

License

MIT - Copyright (c) 2026 Sitharaj Seenivasan