Getting Started with LPI

Local Proxy Inspector (LPI) is a powerful tool for debugging webhooks and HTTP traffic during development. Built by a developer who refused to pay ngrok $10/month, LPI gives you complete control over your webhook debugging workflow.

What is LPI?

LPI is a local HTTP proxy that:

  • Captures all HTTP requests and responses passing through it
  • Provides a real-time web interface for inspecting traffic
  • Works offline - no internet connection required
  • Supports unlimited instances - run as many as you need
  • Keeps your data local - nothing is sent to third-party servers

Quick Start

1. Download LPI

First, identify your platform to download the correct binary.

2. Make it Executable

Windows: No action needed - .exe files are executable by default

macOS/Linux:

chmod +x lpi-darwin-x64   # or your specific binary

3. Run LPI

./lpi   # macOS/Linux
lpi.exe # Windows

This will:

  • Start the proxy server on http://localhost:8091
  • Open the web UI at http://localhost:8080

4. Send Your First Request

Test LPI with curl:

curl -X POST http://localhost:8091/test \
  -H "Content-Type: application/json" \
  -d '{"message": "Hello LPI!"}'

You'll see this request appear instantly in the web UI!

Common Use Cases

Debugging Webhooks

  1. Point your webhook service to http://localhost:8091/your-endpoint
  2. Use a tunnel service to expose LPI to the internet
  3. Watch requests flow through in real-time

API Development

  1. Configure your app to proxy through localhost:8091
  2. Make API calls normally
  3. Inspect all requests and responses in the LPI interface

Testing Integrations

  1. Set up your integration to use LPI as a proxy
  2. Trigger test events
  3. Debug issues by examining the exact data being sent

Key Features

Real-time Monitoring

  • See requests as they happen
  • No refresh needed
  • Filter by method, status, or path

Detailed Inspection

  • View complete headers
  • Pretty-printed JSON bodies
  • Response times and status codes
  • Raw request/response data

Developer Friendly

  • Zero configuration required
  • No account or API key needed
  • Works completely offline
  • Unlimited request history (while running)

Why Choose LPI?

vs ngrok

  • One-time purchase vs monthly subscription
  • Unlimited instances vs instance limits
  • Works offline vs requires internet
  • Your data stays local vs data through third-party servers

vs Burp Suite / Charles

  • Purpose-built for webhooks vs general proxy tools
  • Modern web UI vs desktop applications
  • Instant setup vs complex configuration
  • Lightweight vs resource-heavy

Architecture

LPI consists of two components:

  1. Proxy Server (port 8091) - Captures all HTTP traffic
  2. Web Interface (port 8080) - Displays captured requests

Both run locally on your machine with no external dependencies.

Next Steps

Need Help?