Master double-entry bookkeeping ledgers, transaction isolation, PCI-DSS tokenization, and cryptographically signed webhooks.
Generate RSA/WebCrypto keypairs and verify client request signatures.
Write PostgreSQL 'SELECT FOR UPDATE' queries to prevent race conditions during balance transfers.
Build an HMAC-SHA256 signature validator middleware for payment webhooks.
Implement an in-memory token bucket algorithm for API rate limiting.
Build a RESTful Go/Node service managing double-entry accounting ledgers.
Build an interactive React payment checkout UI supporting cards & mobile money.
Full-stack PCI-compliant payment gateway with real-time merchant dashboard and live webhooks.