Transaction Management System

Problem

Financial transaction systems must stay correct under heavy concurrency — no double-spends, no lost writes — while meeting compliance requirements.

What I built

• Enforced ACID safety under concurrency with optimistic/pessimistic locking and idempotency keys.
• Built audit logging and rule-based fraud detection on FastAPI for regulatory compliance.
• Load-tested with Locust to validate behavior under concurrent load.

Impact

• Sustained 300+ transactions/sec at under 200ms average response with 100 concurrent users.
• Held ACID guarantees under concurrent load via locking + idempotency keys.

Stack