IPInfo API

An open source IP geolocation API that provides detailed information about IP addresses, including geographic location, ISP details, and network information. Compatible with ipinfo.io response format.

Features

• 🌍 Geographic Location: City, region, country, postal code, timezone
• 🏢 ISP Information: Organization name with human-readable mappings
• 🔍 Hostname Resolution: Reverse DNS lookup with timeout
• 🚫 Bogon Detection: Identifies private, reserved, and special-use IP addresses
• 🔄 Auto-updating Databases: Hourly checks for MaxMind GeoLite2 database updates
• ⚡ Fast Response: Optimized for speed with concurrent operations

Quick Start

1. Clone and run:

   git clone https://github.com/tristandevs/ipinfo-api
   cd ipinfo-api
   go run main.go

2. Server starts on port 8080

API Usage

Get your own IP information

curl http://localhost:8080/

Get information for a specific IP

curl http://localhost:8080/208.67.222.222

Response Format

Public IP Response

{
  "ip": "208.67.222.222",
  "city": "San Francisco",
  "region": "California",
  "country": "US",
  "loc": "37.764200,-122.399300",
  "org": "AS36692 CISCO-UMBRELLA",
  "postal": "94107",
  "timezone": "America/Los_Angeles"
}

Private IP Response

{
  "ip": "192.168.1.1",
  "bogon": true
}

Error Response

{
  "status": 404,
  "error": {
    "title": "Wrong ip",
    "message": "Please provide a valid IP address"
  }
}

Supported Headers

The API automatically detects client IP from these headers:

• X-Forwarded-For
• X-Real-IP
• CF-Connecting-IP (Cloudflare)

Database Updates

The service automatically:

• Downloads GeoLite2 databases on first run
• Checks for updates every hour
• Uses atomic file replacement to prevent corruption
• Compares Last-Modified headers for efficient updates

Database sources:

• GeoLite2-ASN.mmdb
• GeoLite2-City.mmdb
• GeoLite2-Country.mmdb

Configuration

Timeouts

• DNS lookup: 40ms context timeout, 50ms total timeout
• Database update checks: 10s
• Database downloads: 60s

ISP Mappings

The service includes human-readable mappings for major ISPs including:

• Cloud providers (AWS, Google Cloud, Microsoft Azure)
• CDNs (Cloudflare, Fastly)
• Major ISPs (Comcast, Verizon, AT&T, Charter)
• Hosting providers (DigitalOcean, Linode, Rackspace)

Requirements

• Go 1.19+
• Internet connection for database updates
• ~100MB disk space for databases

Contributing

Contributions welcome! Please feel free to submit issues and pull requests.