Financial Gateway API

A payment gateway that unifies multiple providers (bill payments, fund transfer, e-loading) behind one API, designed around resilience: automatic failover on transaction errors and idempotent processing so retries never double-charge. Independent reference implementation, built from general gateway-design patterns — no employer code, credentials, or schemas.

• Unifies several payment providers behind a single gRPC + REST surface
• Automatic failover and idempotent transaction handling
• Observability with Prometheus metrics and structured logging