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Fraud Detection API

We Stop
Fraud.
Before It
Hides.

Fake users cost you money. Sentinel tells you if a visitor is a real person or a fraudster hiding behind a VPN, proxy, or bot, so you can block them before damage is done.

GDPR Compliant No PII Stored REST API
5-minute integration
No credit card
Unlimited free tier
Live Risk Assessment
Analyzing now

Analyzing your connection

Evaluating network origin and device signals…

Checking network origin
Detecting VPN / proxy signals
Scanning for antidetect browsers
Evaluating device integrity
Risk Assessment
Evaluating...
--
Network Origin
ISP / Service
VPN / Proxy
Device Intel
Network Intelligence
VPN ,
Proxy ,
Datacenter ,
Tor Exit ,
Country ,
Risk Score ,
Device Intelligence
Antidetect ,
Bot ,
Incognito ,
VM ,
IP Blocklist ,
Visitor ID ,
Live · last 24h
Threats blocked
Identities checked
Developers
GDPR· SOC 2 (in progress)· GitHub ↗
< 40ms
Global Latency
400+
Signals Checked
Free
Always, No Limits
REST
API Core
01
Detect What Others Miss

Fraudsters use tools to make themselves look like normal users from home internet connections. Other fraud tools can't see through this. Sentinel can, catching the threats everyone else misses.

02
From Enrichment to Intelligence

Every visitor gets checked against 20+ signals, their network, device, location, and behavior. You get a simple yes/no answer: is this person real, or a threat?

03
Trusted by Experts, Proven at Scale

Teams who switch to Sentinel don't go back. It plugs into your existing setup in minutes, works in real time, and there are no hidden fees or long-term contracts.

Residential Proxy Detected
HIGH RISK
50.127.134.73
TypeResidential Proxy
ServiceBright Data Network
Devices47 active
ASNAS12345
VPN Exit Node
BLOCKED
95.150.30.146
ServiceNordVPN
InfrastructureData Center
Exit LocationAmsterdam, NL
Antidetect Browser Detected
SPOOFED
GoLogin / Kameleo
TamperingDetected
Anomaly Score0.97
Visitor IDxK8mN2vQ…

Up and running
in minutes.

Three steps. No infrastructure changes. No friction for real users.

01, EMBED
Embed the SDK

Drop one script tag onto your page. Sentinel invisibly collects a session token from every visitor, no cookies required.

<script src="sentinel.js"></script>
02, ASSESS
Call the API

Forward the token from your backend using your API key. One POST request returns a full risk assessment in under 40ms.

POST /v1/evaluate
03, ACT
Act on the Signal

Block, challenge, or flag based on isSuspicious. Your rules, your logic, zero lock-in.

data.isSuspicious → block

Every threat vector,
covered.

One simple API call checks for every type of fraud, bots, VPNs, fake accounts, and more.

Residential Proxy Detection

Catch fraudsters who disguise their location using home internet connections, rotating proxies, and datacenter servers.

Antidetect Browser Detection

Detect Kameleo, GoLogin, AdsPower, Dolphin, and other antidetect browsers. Fingerprint tampering, spoofed canvases, and faked device profiles can't hide.

AI Bot Detection

Detect AI-powered bots that click, scroll, and type like real humans, the new generation of fraud that bypasses CAPTCHAs.

Account Takeover Prevention

Block attackers who try thousands of stolen passwords against your login page, before they get in.

VPN & Tor Exit Detection

Know when someone is hiding their identity through a VPN or the Tor network, and see exactly which country they're really in.

REST API, Any Stack

Works with any programming language or platform. Add one API call to your code and you're protected.

Sentinel
in action.

Watch a live evaluation, from API call to risk decision, in real time. Click play to run the demo.

[ View Full Docs → ]
Watch Demo
POST /v1/evaluate, Live Demo
sntlhq.com
Request
fetch('https://sntlhq.com/v1/evaluate', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer sk_...'
  },
  body: { token: }
});
Sending request…
Response ✓ 23ms
{
  "isSuspicious": false,
  "score": 0,
  "details": {
    "vpn": false,
    "proxy": false,
    "ip": "84.15.201.92"
  }
}
SAFE · Score 0
No threats detected

See how fraud detection stops chargebacks, fake accounts, and trial abuse.

Case Study
How a Creator Platform Cut Fraudulent Pledges by 94%, Without Adding Friction

Automated carding bots were flooding checkout with stolen cards. Sentinel identified the scripts in 48 hours and shut them down completely, lifting legitimate pledge rates 12%.

[ Read Case Study → ]
Case Study
A B2B SaaS Recovered $2.1M in Revenue by Blocking Proxy-Based Trial Abuse

Competitors were spinning up proxy-masked accounts to scrape pricing data and burn through trial credits. One API integration stopped it cold in a single afternoon.

[ Read Case Study → ]
Case Study
How an E-Commerce Brand Saved $340K in 30 Days by Catching Chargebacks Before They Filed

A coordinated friendly-fraud ring was filing chargeback disputes at scale using residential proxies. Sentinel's behavioral layer flagged the pattern before a single dispute was processed.

[ Read Case Study → ]

We beat IPQS, Spur,
Sift, and DataDome.

Faster detection, higher accuracy, and actually free. No sales calls, no contracts.

Feature Sentinel IPQS Spur Sift DataDome
Free tier ✓ Unlimited 5,000/mo ✗ Paid only ✗ Enterprise ✗ Enterprise
API Latency (p99) < 40ms ~200ms ~120ms ~500ms+ JS-inject only
Setup time < 5 min ~1 hour ~2 hours Days + sales Days + proxy
VPN / Proxy detection Limited
Residential proxy detection Weak
Antidetect browser detection
Device intelligence ✓ Full Basic Basic
No PII stored (GDPR) ✓ By design Stores IPs Stores IPs Stores data Stores logs
Free Forever, No Card Required

Start protecting
your platform today.

No credit card. No usage limits. Integrate in under 5 minutes.

GDPR Compliant  ·  No PII Stored  ·  Open API

Signals per check: 400+
Free tier: 10,000 req/mo
API Latency: < 40ms