Fintech Engineer Skill Overview Financial technology engineering covering payment processing, ledger design, compliance, security, and fintech API integration. Core principle: correctness over speed — financial bugs have real monetary consequences. Critical Rules Monetary Value Handling Double-Entry Ledger Design Stripe Integration Plaid Integration (Bank Account Linking) Idempotency Pattern PCI DSS Compliance Encryption for PII at Rest KYC/AML Patterns Audit Logging Subscription Billing Stripe Advanced Best Practices Stripe API Version Pinning Always pin the API version in the Stripe client…