REST API v2.4

Fraud Detection API

Analyze transactions in real-time with Vigil's multi-signal fraud scoring engine. One POST request returns a risk score, verdict, and detailed signal breakdown.

Base URL
vigil.nanocorp.app
Latency
< 50ms p99
Auth
Bearer Token
Format
JSON

01Endpoint Reference

POST/api/analyzeAnalyze transaction for fraud

Request Body Parameters

ParameterTypeRequiredDescription
amountnumberrequiredTransaction amount in the specified currency
currencystringoptionalISO 4217 currency code (default: USD)
countrystringrequiredISO 3166-1 alpha-2 country code of the buyer
emailstringrequiredCustomer email address
ip_addressstringoptionalCustomer IP address for geo-correlation
card_binstringoptionalFirst 6 digits of the card number
velocity_24hintegeroptionalNumber of transactions from this user in the last 24h
merchant_categorystringoptionalMerchant category for contextual scoring
is_recurringbooleanoptionalWhether this is a recurring/subscription payment
transaction_idstringoptionalYour internal transaction ID for tracking

02Response Format

200 OKapplication/json
{
  "transaction_id": "txn_1709832456_a8f3k2",
  "risk_score": 0.72,
  "risk_level": "high",
  "verdict": "REVIEW",
  "signals": [
    {
      "signal": "HIGH_RISK_GEO",
      "description": "Origin country NG is classified as high-risk",
      "severity": "high",
      "score_impact": 0.30
    },
    {
      "signal": "HIGH_VELOCITY",
      "description": "7 transactions in 24h — above normal threshold",
      "severity": "high",
      "score_impact": 0.20
    }
  ],
  "metadata": {
    "model_version": "vigil-v2.4.1",
    "engine": "rule_ensemble_v3",
    "evaluated_at": "2026-03-07T14:23:01.456Z",
    "latency_ms": 23,
    "signals_evaluated": 4
  }
}
APPROVE
score: 0.00 – 0.29

Low risk. Safe to process the transaction automatically.

REVIEW
score: 0.30 – 0.69

Moderate risk. Flag for manual review or step-up auth.

DECLINE
score: 0.70 – 1.00

High risk. Block the transaction and alert the customer.

03Integration Examples

curl -X POST https://vigil.nanocorp.app/api/analyze \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer vgl_sk_live_..." \
  -d '{
    "amount": 299.99,
    "currency": "USD",
    "country": "US",
    "email": "customer@example.com",
    "ip_address": "73.162.45.89",
    "card_bin": "411111",
    "velocity_24h": 2,
    "merchant_category": "electronics"
  }'

04Interactive Demo

Paste a transaction JSON below and see how Vigil scores it in real-time. Try the presets or craft your own.

request.json
POST /api/analyze
response.json

Click "Analyze" to see results

05Signal Reference

SignalTriggerSeverityScore Impact
HIGH_AMOUNTAmount > $10,000high+25%
ELEVATED_AMOUNTAmount > $5,000medium+12%
ROUND_AMOUNTExact round number (e.g., $5,000)low+5%
HIGH_RISK_GEOCountry in high-risk list (NG, RU, etc.)high+30%
ELEVATED_GEO_RISKCountry in medium-risk list (BR, IN, etc.)medium+10%
DISPOSABLE_EMAILDisposable email provider detectedcritical+35%
SUSPICIOUS_EMAIL_PATTERNAuto-generated email patternmedium+15%
EXTREME_VELOCITY> 10 transactions in 24hcritical+35%
HIGH_VELOCITY> 5 transactions in 24hhigh+20%
CRYPTO_CURRENCYCryptocurrency payment detectedmedium+15%
RECURRING_PAYMENTRecurring/subscription paymentlow-10%

06Authentication & Rate Limits

Authentication

Include your API key in the Authorization header of every request.

Authorization: Bearer vgl_sk_live_...

Rate Limits

Starter1,000 req/min
Growth10,000 req/min
EnterpriseUnlimited