// SUMMARY
Senior Backend Engineer and Technical Lead with six years of experience architecting distributed systems, financial payment switch integrations, and high-throughput microservices. Core expertise in Go, TypeScript, Node.js, PostgreSQL, Kafka, and Kubernetes. Led development of Pakistan domestic payment routing (Raast ISO 20022, 1LINK, JazzCash, Easypaisa) handling 45,000 requests per minute with 99.99% uptime and sub-120ms p99 latency.
// FEATURED SYSTEMS & PROJECTS
Raast ISO 20022 Instant Payment Connector
https://github.com/rafayhashmi/raast-iso20022-switch
Production-ready financial switch module implementing State Bank of Pakistan Raast instant payment rails with cryptographic payload signing and HSM authentication.
Distributed Webhook Replay & Dead-Letter Worker
https://github.com/rafayhashmi/webhook-replay-worker
High-throughput resilient webhook processor handling up to 30,000 events/minute with exponential backoff and idempotency guarantees; open-sourced after enterprise battle-testing.
// PRODUCTION EXPERIENCE
Technical Lead – Backend Engineering
February 2021 to Present
FinTech Velocity / Systems Limited
- Architected distributed transaction switch processing Rs. 4.2B in monthly payments across 1LINK, SBP Raast, JazzCash, and Stripe with 99.99% uptime.
- Optimized PostgreSQL connection pooling, read-replicas, and query execution plans; decreased p99 API latency from 340ms to 92ms under peak flash-sale loads.
- Executed live zero-downtime migration of a 900GB relational database with checksum verification across 240 tables in 38 scheduled minutes.
- Constructed automated dead-letter queues and retry workers with BullMQ and Redis, reducing transaction settlement failure rates by 46%.
- Supervised and coached 7 software engineers across sprint planning, code reviews, and automated CI/CD pipeline deployments.
Software Engineer
January 2019 to January 2021
10Pearls Pakistan
- Engineered high-concurrency microservices in Go and Node.js for US enterprise logistics and SaaS clients.
- Designed JWT token rotation and RBAC authorization microservice, slashing security-related support tickets by 55%.
- Automated Docker Compose testing rigs and GitHub Actions deployment pipelines for 8 microservices.
- Authored comprehensive API contracts and Swagger/OpenAPI documentation for third-party developer integrations.
Junior Software Developer
July 2018 to December 2018
Arbisoft
- Developed RESTful CRUD endpoints in Python and Node.js for client inventory and order management systems.
- Implemented unit and integration test suites reaching 85% code coverage with Jest and Mocha.
// TECHNICAL ACHIEVEMENTS & MILESTONES
- Architected financial payment switch handling Rs. 4.2B monthly volume with zero critical production downtime.
- 1st Place Winner - National FinTech Hackathon (Organized by SBP & Ignite).
- Reduced cloud AWS infrastructure bills by $3,200/month through container rightsizing and Aurora auto-scaling.