Principles before libraries
Read the constraints of the problem before picking a tool. Tools change every few years; the way data moves and the way failures spread do not.
Backend Engineer · Ho Chi Minh City, Vietnam
Systems that actually run.
Not demos.
Backend in TypeScript for Singapore clients — APIs, data, queues, payments. I take the work from architecture and third-party integrations through to deployment and the runbook.
- LanguageTypeScript · Node.js
- DataPostgreSQL · MongoDB · Redis
- InfrastructureAWS · Docker · Nginx
- Applied AIOpenAI · RAG · Pinecone
Engineering
Four problems
I have solved.
- 01 Payments: many gateways, one state flow Charge first, write the order inside a transaction, and only then reach the refund and reconciliation boundary. Five different gateways still have to produce exactly one state flow — no order left hanging in between.
-
02
Queues that never duplicate a record
Bull/BullMQ with idempotency keys, row locks via
FOR UPDATE SKIP LOCKEDand side effects that tolerate at-least-once delivery. Retries, TTL and concurrency limits are part of the design, not something improvised during an incident. - 03 Multi-tenant, with the tenant chosen by domain Hostname normalisation, then a header guard, then relation-level scoping. One backend serves many branded sites while 314 migrations and 92 entities stay under control.
-
04
OCR and vector search in one pipeline
PDFs up to 50MB go through a priority queue and
worker_threadsinto OCR, with TTL-scoped storage; the output is text ready for embeddings and semantic search. Heavy jobs are concurrency-capped so they never drag the API down.
How I work
Three things I
do not trade away.
Transaction boundaries are design
Where to write, where to refund, where to reconcile are decisions made before the first line of code — not patches after a transaction goes out of balance.
A runbook is part of the feature
A system is finished only when someone else can run it without asking the author: deploy, rollback, health checks, and knowing where it usually breaks.
About
A little
about me.
I am Phan Gia Phát, a backend engineer working mostly with Node.js and TypeScript. I design, build and operate production systems for Singapore clients, most of them end to end on my own.
Most of the work sits where it is hard to see: transaction boundaries when a payment fails halfway, multi-tenancy where the tenant is chosen by domain, queues that never produce a duplicate row, and runbooks good enough for whoever comes next. I would rather read the principle than the tutorial.
- Work
- Backend Engineer — production systems for Singapore clients.
- Education
- Engineer's degree in Information Technology — Saigon University.
- Certification
- Huawei Cloud HCCDA — Tech Essentials.
- Going deeper
- DSA, the JavaScript runtime and backend architecture — from first principles, not tricks.
Contact
Let's build
something that lasts.
If you have a role in mind, or just want to talk through a backend problem — get in touch.