React Native app enabling instant cross-border transfers with biometric auth, real-time FX rates, and compliance checks across 12 currencies.
A FinTech startup needed a consumer-facing cross-border payment app that could clear regulatory requirements in Japan, UK, and Singapore simultaneously. Existing solutions were too slow, too expensive, or couldn't handle multi-currency wallets with real-time FX.
React Native codebase with iOS/Android parity. Plaid for bank account linking, a custom FX rate aggregator polling 4 providers, and a compliance engine that runs KYC/AML checks synchronously before any transfer initiates. All PII encrypted at rest with AES-256.
Shipped to App Store and Play Store in 18 weeks. 4.8-star average rating from 2,000+ early users. Sub-2-second transfer confirmation. Zero compliance incidents in the first 6 months of operation.
TECHNICAL DEPTH
Biometric auth (Face ID / Fingerprint) as the primary auth factor with PIN fallback. JWT refresh tokens stored in iOS Keychain / Android Keystore — never in AsyncStorage. Certificate pinning prevents MITM attacks on the API layer.
Custom rate aggregator polls 4 FX providers every 30 seconds, applies a spread, and locks the rate for 90 seconds during checkout. Redis stores the locked rate with TTL. Expired rates reject the transaction — no rate mismatch risk.
KYC via Jumio SDK integrated into onboarding. AML screening runs on every transfer via Sardine API. Flagged transactions enter a manual review queue with 24-hour SLA. Full audit trail stored in append-only PostgreSQL tables.