# Hai Hoang Van

**Senior Fullstack Engineer**

📍 Hanoi, Vietnam
📞 +84 966 041 057
📧 haihv27@gmail.com
🔗 [Portfolio](https://haihv.dev) | [GitHub](https://github.com/haihv) | [LinkedIn](https://www.linkedin.com/in/haihv96)

## Professional Summary

Senior Fullstack Engineer with 9+ years building end-to-end web applications. Proficient in TypeScript, React/Next.js, Node.js/NestJS, and Golang, with proven ability to architect scalable systems and deliver complete features from database to UI. Built e-commerce platform powering $4M/month operations and multiple Web3/Solana dApps for global clients.

## Core Skills / Tech Stack

- **Frontend:** Next.js, React, Nuxt.js, Vue.js, TypeScript, TailwindCSS, ChakraUI
- **Backend:** Node.js, NestJS, Express.js, Python, Golang, Prisma, REST APIs, GraphQL, gRPC, tRPC
- **Database:** PostgreSQL, MySQL, Redis, Database Design, Query Optimization
- **Testing:** Test-Driven Development (TDD), Playwright, Cypress, Jest, Vitest
- **DevOps & Tools:** Docker, CI/CD, AWS, Kubernetes, Kafka
- **Architecture:** Microservices, Domain-Driven Design (DDD), System Design, API Design

## Key Projects

- **E-commerce Platform:** Full-stack e-commerce with **microservices backend** (Node.js) and **Nuxt.js storefronts**, powering **$4M/month** dropshipping operations with checkout and payment processing.
- **Web3 Applications:** Full-stack dApps across **DID, KYC, prediction, and gaming** domains with **Solana/EVM integrations**, **NestJS/Golang backends**, and **React frontends** with wallet connections.
- **Healthcare SaaS:** End-to-end infusion-center platform using **T3 stack** (Next.js, tRPC, Prisma) with **FHIR-compliant APIs**, serving top US clinics with **Playwright e2e testing**.

## Open Source

- **[valifetch](https://github.com/haihv/valifetch):** Type-safe HTTP client built on native fetch with Valibot schema validation, featuring automatic type inference, retry logic, and request/response hooks.
- **[nestjs-solana-kit](https://github.com/haihv/nestjs-solana-kit):** NestJS integration for Solana @solana/kit v5.x, providing 12 production-ready services for account operations, transaction building, and WebSocket subscriptions.

## Professional Experience

### Moonraise – Web3 development on Solana and EVM ecosystems

_Senior Software Engineer — Feb 2024 – Feb 2026_

- Delivered **full-stack dApps** for **global clients** across multiple domains, building Next.js/React frontends and **NestJS/Golang backends**.
- Designed **RESTful APIs and database schemas** (Prisma ORM) with **Redis caching**, optimizing query performance for blockchain data.
- Implemented **Solana programs with Anchor** for on-chain logic and token operations.

### Endue – US healthcare startup, SaaS platform for infusion centers

_Senior Software Engineer — May 2023 – Jan 2024_

- Built **full-stack features** using **T3 stack** with type-safe API layer (tRPC), database modeling (Prisma), and Next.js frontend.
- Designed **database schemas** for complex healthcare data (patients, appointments, etc.) and implemented **FHIR-compliant APIs**.
- Integrated **LaunchDarkly** for feature flags, A/B testing, and gradual rollouts.
- Deployed comprehensive **Playwright e2e tests** covering critical user flows.
- Optimized **CI/CD pipelines** reducing build time and Docker image size.

### Depocket – Crypto on-chain tracking and portfolio management

_Senior Software Engineer — Apr 2022 – Mar 2023_

- Built **full-stack features** including new frontend version and **backend APIs** (Golang) for blockchain data aggregation with **Redis caching**.
- Implemented **EVM chain integrations** on both backend (Web3.js, Ethers.js) and frontend (wallet connections, transaction signing).
- Optimized **database queries and indexing** for fast portfolio calculations across multiple chains and wallets.
- Set up **CI/CD pipelines** for automated testing and deployment.

### LessonBox – EdTech platform for digital learning objects

_Senior Software Engineer — Apr 2021 – Mar 2022_

- Built **full-stack features** with React frontend and **NestJS microservices** for content management, authentication, and progress tracking.
- Designed **database schemas** for learning content, user progress, and assessment data with efficient querying patterns.
- Optimized **backend performance** with caching strategies and database query tuning.
- Set up **CI/CD pipelines** with GitHub Actions deploying to **Kubernetes (EKS)**.

### Upatra – Shopify app development studio

_Senior Software Engineer — Sep 2020 – Mar 2021_

- Developed **Shopify apps** with Python backends and React/Vue frontends.

### UPLUS Solutions & Technologies – E-commerce solutions for checkout and dropshipping

_Fullstack Software Engineer — Jan 2018 – Aug 2020_

- Built **frontend storefronts** (Nuxt.js with SSR) and **admin dashboards** (Vue.js) for e-commerce platform handling **50K paid orders/month**.
- Optimized **storefront performance** for faster page loads and improved conversion rates.
- Implemented **Cypress e2e testing** covering critical user flows.
- Refactored and enhanced **legacy backend systems** (Python) for checkout flows and order management.

### Enzimify – Shopify app development startup

_Junior Software Engineer — Feb 2017 – Dec 2017_

- Developed **Shopify apps** (Express.js, Vue.js) with **Kafka** data processing pipelines on **AWS**.
- Built **backend services** with Shopify API integrations, webhook processing, and event tracking systems.

## Education & Awards

- **Hanoi University of Science and Technology**
- **Vietnam Mathematical Olympiad Award — Hung Yen Specialized High School**