Building scalable systems with microservices, realtime architecture, and AI.
I design and ship production systems that handle complexity without cutting corners.
Featured Projects
O2SKIN
A clinic management platform serving multiple branches with real-time queue tracking, appointment scheduling, and inventory control.
Coordinating 15+ independent service domains (clinic, customer, order, inventory, scheduling) without coupling them tightly, while keeping queue state consistent in real time across branches.
Designed a NestJS microservices architecture with gRPC for synchronous inter-service calls and Redis Pub/Sub for real-time state propagation. Socket.IO pushes live queue and appointment events to connected clients. BullMQ handles all async background jobs.
Reduced appointment conflicts to near zero. Live queue dashboards give clinic staff instant visibility across locations. Unleash feature flags allowed safe rollout of new modules without downtime.
Architecture Thinking
How I design systems that scale
Microservices with gRPC
15+ independent services communicating over type-safe gRPC contracts. Each service owns its data. The API gateway handles auth and routing.
Realtime Event Flow
Redis Pub/Sub as the message backbone. Socket.IO rooms map to business entities. BullMQ ensures async jobs survive restarts.
AI Integration Pipeline
OpenAI API structured outputs parse unstructured PDFs. Background queues handle processing. Results stored with confidence scores for human review.
Experience
Freelance / Solo Projects
Fullstack Engineer
- Built O2SKIN clinic platform with NestJS microservices, gRPC, and Socket.IO real-time features
- Built KitesHR recruitment platform with OpenAI resume parsing and commission payment tracking
- Designed and shipped two production systems end-to-end as a solo engineer
Previous Employer
Fullstack Engineer
- Built scalable real-time chat for web and mobile with Socket.IO and MongoDB
- Developed Telesales and CRM system for lead management and call scheduling
- Handled server operations, deployment, uptime monitoring, and system maintenance
Technical Expertise
About
I am a fullstack engineer with 4 years of experience building production systems. My focus is on scalable architecture, clean code boundaries, and shipping software that works reliably. I spent the last two years designing and shipping two complex production platforms solo, which sharpened my end-to-end product thinking. I care about systems that are maintainable a year from now, not just working today.
Microservices architecture, realtime systems, AI-assisted tooling, clean API design.
Computer Engineering (IT2), 2019-2024
Dinh Cong, Hoang Mai, Hanoi, Vietnam
Let's build something impactful together.
Available for fullstack engineering roles. Open to remote, hybrid, or on-site in Hanoi.
Nguyen Cong Tien / Fullstack Developer / 2026