Backend Engineer — Fintech Infrastructure & Distributed Systems
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Backend engineer specializing in fintech infrastructure and distributed payment systems.
I build production-grade backend systems focused on reliability, low latency, and financial correctness — idempotency, circuit breakers, reconciliation, and fraud detection. Currently working on high-frequency trading infrastructure and open-source payment tooling.
A production-grade distributed payment system built to solve real fintech reliability problems:
- Circuit Breaker (CLOSED → OPEN → HALF-OPEN) — prevents cascading failures when downstream services degrade. Tested full lifecycle under real service outage.
- Smart Retry with Error Classification — non-retryable errors (insufficient funds, card expired) abort immediately. Retryable errors use exponential backoff with jitter — eliminates thundering herd on recovery.
- End-to-End Idempotency — dual-layer: Redis fast-path + PostgreSQL unique constraints as truth-path fallback. Guarantees exactly-once processing under concurrent duplicate requests.
- Reconciliation Engine — cross-checks payment records against append-only wallet ledger. Detects 4 mismatch types including completed payments with no wallet debit and failed payments with unexpected charges. Processes records in 17ms.
- Redis-backed Anomaly Detection — 4 real-time fraud rules (velocity, large amount, failed streak, duplicate amount). Non-blocking by design — flags attacks without rejecting legitimate payments.
- Load tested with k6 — 50 concurrent users, 51 req/sec, p50=9ms, p95=32ms.
Stack: Node.js TypeScript PostgreSQL Redis Docker
| Area | Technologies |
|---|---|
| Backend | Node.js, TypeScript, Express, REST APIs |
| Fintech | Payment Systems, Idempotency, Circuit Breaker, Distributed Locking, ACID Compliance |
| Databases | PostgreSQL, Redis, MongoDB, MySQL |
| Infrastructure | Docker, AWS (ECS, ECR, CloudWatch), GCP, CI/CD |
| Observability | Prometheus, Grafana, Signoz |
| Languages | TypeScript, JavaScript, Python, C++ |
- token-management-api — Distributed token system with Redis + Docker for short-lived secure access control
- Incident_tracker — Incident management and tracking prototype
- MCP-Gemini-Tool-Agent — AI command agent using Google Gemini and Model Context Protocol for real-world task execution
- NexusTimer #475 — Merged PR
- NexusTimer #469 — Merged PR
- DebugFest/snake-game #14 — Merged PR
- LeetCode 1850+ (Top 5%) — Codeforces 1400+ — GFG Institute Rank #3
- Written technical articles on distributed systems and fintech engineering
Open to backend engineering roles in fintech, infrastructure, and distributed systems.