If you're building an application that needs to detect VPNs, proxies, or Tor exit nodes, you need a reliable API. Here's a practical comparison of the best free options in 2026.

Why Detect VPNs?

VPN detection isn't about blocking privacy-conscious users. It's about preventing:

  • Account creation abuse (one person, hundreds of accounts)
  • Geo-restriction bypass (accessing region-locked content)
  • Payment fraud (hiding true location during transactions)
  • Credential stuffing attacks (masking bot traffic)
  • Price scraping and competitive intelligence theft

Top Free VPN Detection APIs

1. Sentinel (sntlhq.com)

Free tier: 1,000 requests/hour (no monthly cap)
Response time: < 40ms
Detection: VPN, proxy, residential proxy, Tor, datacenter, antidetect browsers, bots

Sentinel stands out by combining IP intelligence with device fingerprinting. It's the only free API that detects antidetect browsers and browser tampering in addition to VPN/proxy detection.

// Node.js example
const result = await fetch('https://sntlhq.com/v1/evaluate', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer sk_live_YOUR_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({ token: sentinelToken })
});
const data = await result.json();
console.log(data.isSuspicious); // true if VPN/proxy detected
console.log(data.details.vpn);  // boolean
console.log(data.details.proxied); // boolean

2. IPQualityScore

Free tier: 5,000 requests/month
Response time: 150-400ms
Detection: VPN, proxy, Tor, datacenter

IPQS is the most widely used IP reputation API. Good for basic VPN/proxy detection but lacks device-level intelligence.

3. ip-api.com

Free tier: 45 requests/minute (HTTP only)
Response time: ~100ms
Detection: Basic geolocation + limited proxy detection

ip-api is a simple geolocation API with basic proxy detection. The free tier is HTTP-only (no HTTPS), which limits production use.

4. vpnapi.io

Free tier: 1,000 requests/day
Response time: ~200ms
Detection: VPN, proxy, Tor, relay

Focused specifically on VPN detection. Simple API but no device intelligence or bot detection.

Which Should You Choose?

For most developers, Sentinel offers the best combination of generous free tier, fast response time, and comprehensive detection. If you need email/phone validation alongside IP checks, consider IPQS as a complement.

The most important thing: don't rely on IP reputation alone. Modern fraudsters use residential proxies with clean IPs. Combining network intelligence with device fingerprinting is the only way to catch sophisticated attacks in 2026.

Get Started

Sign up at sntlhq.com — get your API key in 2 minutes, no credit card required. Full documentation at sntlhq.com/api.