HAO.SYS

Backend Developer / Ho Chi Minh City / UTC+7

BUILT FOR100 MILLIONUSERS.

I'm Hao Nguyen The. I design the invisible half of software — queues, caches and pipelines in NestJS, PostgreSQL, Redis, Elasticsearch— for systems that can't afford to go down. Like a national identity platform for an entire country.

0citizens designed for
0faster pipeline
0test coverage
Hao Nguyen The
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[01]

Mission Log

Trident Digital Tech // Backend Developer

JUL 2025 → PRESENT · HCMC

RDC — National Citizen Management Platform

gov-tech · congo · national scale
  • National-scale system needed a resilient backend; architected NestJS microservices separating core APIs, async eKYC workers and cron jobs — designed for 100M+ citizens
  • Large citizen datasets caused DB bottlenecks; applied Redis + Bloom Filter caching and BullMQ async queues, cutting DB load and decoupling OCR/face recognition from the API cycle
  • Identity verification required a secure, auditable flow; built an eKYC workflowwith Tencent Cloud OCR & Face Recognition, JWT auth, RBAC and AES encryption
  • Citizens had to be reconciled against national registries; built verification-source linking against external providers (ONIP, CENI) with auto/manual linking, duplicate-prevention and a two-step manual enrollment flow
  • Fraud & abuse risks on lookups; added rate-limiting on national-ID enquiry and per-API permission configuration (RBAC)
  • Records needed flexible search and full auditability; configured Elasticsearch full-text search, designed PostgreSQL schemas with migrations, and streamed user-event logs to ClickHouse for the analytics/audit trail

Trifood — Food Delivery & Surplus Marketplace

e-commerce · high traffic
  • APIs needed to be reliable and well-tested; built the Surplus Bagmodule and merchant order/product/payment endpoints (NestJS) with cart & order validation — 70%+ test coverage via Jest
  • Surplus inventory and variant pricing had to stay consistent; implemented auto-sold-out status, variant price sync on markup changes and a BullMQ + Redis processing pipeline
  • Product search was slow on large catalogs; indexed data in Elasticsearch to power fast full-text queries across the product catalog

Tego Global // Software Developer

DEC 2023 → JUN 2025 · HCMC

Pfs — Insurance Data Crawling

scrapy · selenium · grpc
  • Manual collection took ~5 min/record, unscalable for thousands of entries; built Scrapy + Selenium crawlers (17 spiders) cutting it to <30s/record — 10×+ faster (API sources <3s)
  • Anti-bot protection blocked scraping; bypassed Cloudflare (cloudscraper/cfscrape, rotating user-agents), scaling to 10,000s records/dayacross motor, home, travel & pet insurance (AAMI, Allianz, QBE, CBA, NIB, Covermore…)
  • Crawlers needed orchestration and delivery; built a NestJS backend driving the Python crawler over gRPC, real-time progress via SSE, TypeORM migrations, and JWT + OTP + login-attempt auth with RBAC
  • Needed production infra; used AWS S3, Cognito, RDS, ORM via TypeORM & SQLAlchemy (Alembic migrations) and Redis caching

Perkify — CRM & Loyalty (Vivaleisure)

crm · loyalty · aws-cdk
  • CRM lacked a rewards engine; built loyalty point & redemption features on NestJS + MongoDB, optimizing aggregation queries for faster reporting
  • Multiple roles and channels; developed REST APIs for admin, staff & customers with JWT + Passport (Facebook social login), WebSocket real-time updates, rate-limiting (Throttler) and cron-driven nodemailer email campaigns
  • Deployment was manual and error-prone; provisioned cloud infrastructure as code with AWS CDK — EC2, ECR, ELB, IAM, Lambda, Route 53

Blog & Autosend News — Internal Platform

automation · slack · realtime
  • ~2 hrs/day lost to manual content curation; built an automated Slackintegration via cron jobs delivering tech news & crypto updates — saved ~2 hrs/day
  • Platform lacked real-time features; implemented WebSocket notifications, tree comments and content recommendations via Embeddings, with Redis caching
  • Deployed on NestJS + Prisma + PostgreSQL
[02]

Loadout

Backend
NestJS · Node.js · Next.js · gRPC · WebSocket/SSE
Databases
PostgreSQL · MongoDB · Redis · Elasticsearch · ClickHouse
Languages
TypeScript · JavaScript · Python
Messaging
BullMQ · Redis Queues
Cloud
AWS S3 · EC2 · RDS · Cognito · CDK (IaC)
Infra & Testing
Docker · GitHub Actions · Jest
[03]

Credentials

Degree

B.Eng. Software Engineering

HCMUTE — Ho Chi Minh City
Aug 2021 → Jun 2026

Languages

VI native · EN intermediate

English — TOEIC 740
Comfortable in international teams