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Courtin — Badminton Community & Online Booking Platform
Solves the fragmented, double-booking-prone way local badminton courts are booked by unifying real-time slot booking, VietQR wallet payments, and skill-based matchmaking into one platform — delivered as five domain services behind an API gateway with a React web client.
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Designing and building event-driven microservices — API gateways, domain services, message buses, and concurrency-safe data layers — with a focus on correctness, reliability, and performance under load.
Turning real-world problems into documented business rules, domain models, and role-based workflows — then validating them with automated tests and access-control audits before release.
- Architected 5 Node.js/TypeScript services behind an API gateway, with schema-per-service PostgreSQL and RabbitMQ events via a transactional outbox.
- Built a competitive-match escrow across 3 services: stakes paid via SePay/VietQR → score claim → 12-hour dispute window → admin ruling → payout, settling each match exactly once.
- Refined a 61-use-case baseline into 40 signed-off functions and 198 acceptance criteria, adding a missed flow for unmatched bank transfers.
- Benchmarked 2 competing platforms across 18 feature areas, finding no real-time court booking with payment and positioning Courtin to fill it.
- Optimized the booking write path with a bounded Kafka dispatcher and transactional outbox, raising throughput +74% and cutting p95 latency 41% under k6 load.
- Built the auth service with RS256 JWT, OTP login, and admin MFA, blocking all 11 over-privileged attempts across 15 authorization scenarios.
- Audited the pricing flow and found quoted and booked fares could differ; proposed a time-limited price lock, later built into the system.
- Drafted a 17-flow UAT checklist for customer, driver, and admin apps: OTP login → fare quote → booking → payment → rating.
- Designed 7 Node.js/Express microservices behind an API gateway (JWT, RBAC, rate limiting) with RabbitMQ choreography and an outbox worker, so no event is lost when the broker fails.
- Prevented double booking with a 2-layer lock (Redis SET NX + PostgreSQL advisory lock): 1 of 1,000 concurrent requests won the slot, and idempotency keys merged 500 retries into 1 record.
- Specified 38 use cases across 4 roles (guest, customer, staff, admin) with activity diagrams, covering booking, refunds, check-in, and revenue reports.
- Defined SePay reconciliation rules: DH codes match incoming payments, RF codes match refunds within 7 days, and ambiguous transfers are ignored to protect the ledger.
I’m a fourth-year Information Systems student at the Industrial University of Ho Chi Minh City (IUH), aiming to grow into a Business Analyst and Full-stack Developer. I enjoy sitting between people and technology — understanding what a product actually needs to do, then helping shape it into something people can really use.
Right now most of my energy goes into COURTIN, a badminton booking platform I’m building from the ground up — the kind of project where I turn fuzzy ideas into clear requirements, figure out how the pieces fit together, and follow the work through to a result I’m proud of. I care about clear communication, dependable delivery, and staying curious enough to keep learning. Want to know more about my experience? Download my resume.
OPEN
TO
OPPORTUNITIES
I'm open to opportunities where I can contribute to backend and full-stack development, system design, business analysis, and QA.