Posts about payments. ← All posts
The transaction engine had to absorb 30K+ TPS across partner integrations, never lose a transaction, and survive partial failures. The architecture: Go, Kafka, Pub/Sub, Redis, K8s, with idempotency at every layer.
A single layer of idempotency will eventually fail. Three independent layers gives you a margin. Here is the pattern that worked across ingest, worker, and emit boundaries.
UPI, IMPS, NEFT, RTGS — which rail to use depends on amount, urgency, window, success-rate history. A deterministic chooser with a HITL gate above ₹2 lakh.
UPI is the most popular payment rail in India. The spec is precise. The implementation guides are not. Notes on the integration details that ate weeks the first time.