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API · Machine Learning · Fintech

FraudDetect
API

A real-time transaction fraud detection API that scores each payment across eight independent risk signals — returning a fraud probability, risk tier, and plain-language explanation in under 80ms.

REST API Machine Learning HMAC-SHA256 OpenAPI Railway RapidAPI Webhooks
Live API ↗

80ms

Response Time

8

Risk Signals

4

Risk Tiers

ML

Weighted Model

01 / Problem

Financial fraud is discovered after the loss, not before it

Most fraud detection happens through post-hoc chargeback analysis — by which point the loss has already occurred. Payment processors and fintechs need a way to score transactions before they clear, in real time, without adding latency that kills conversion rates. Building this in-house requires data science infrastructure most teams don't have.

02 / Approach

Eight-signal weighted ML model, sub-80ms response

Each transaction is evaluated across eight independent risk dimensions: spending pattern deviation, device fingerprint recognition, geographic anomaly, transaction frequency, IP reputation history, time-of-day patterns, amount threshold analysis, and transaction category risk. A weighted ML model combines these signals into a single fraud probability score (0–1).

The API returns not just a score but a four-tier classification (LOW / MEDIUM / HIGH / CRITICAL) and a plain-language explanation of the primary signals that drove the decision — giving operations teams actionable context, not just a number. HMAC-SHA256-signed webhooks fire on critical-tier events. A chargeback feedback loop feeds confirmed fraud cases back into model retraining.

03 / Result

Production fraud prevention for fintechs and payment gateways

FraudDetect API integrates in a single API call with no ML infrastructure required. Deployed on Railway with RapidAPI marketplace distribution and a full OpenAPI spec. The freemium tier covers prototyping; Pro unlocks fraud network detection across devices and IPs, custom rule engine, and the merchant analytics dashboard — everything a payment processor needs to run fraud ops at scale.

Key Features
  • Fraud probability score (0–1) in under 80ms
  • Four-tier classification: LOW / MEDIUM / HIGH / CRITICAL
  • Plain-language explanation of flagging signals
  • Fraud network detection across devices and IPs
  • Custom rule engine for business-specific logic
  • Velocity limits to block burst and replay attacks
  • HMAC-SHA256-signed webhook alerts
  • Chargeback feedback loop for continuous model retraining