Thi Han Hein

Full Stack Engineer | Java· TypeScript · AWS · PostgreSQL · Node.js | Sydney

Camperdown, New South Wales, Australia

About

Backend engineer with 4+ years building scalable APIs, data pipelines, and AI-driven systems for B2B SaaS products. I specialise in Node.js, TypeScript, Java and AWS, designing backend services that stay reliable at scale and integrating LLMs to automate complex workflows. Most recently, I built SamanthaAI: an AI-powered data extraction platform using Claude and Gemini APIs that achieved 99%+ accuracy and eliminated 100% of manual data entry. I thrive in small, high-ownership teams where I can shape both the product and the engineering culture — remote-friendly and currently based in Sydney. Open to backend and full-stack roles in product-led or mission-driven startups. 🔗 Portfolio: https://micaljohn60.vercel.app/

Experience

  • Backend Engineer (Remote) at Onlynx Tech
    Jun 2024 - Present · 2 yrs 1 mo

    - Designed and maintained scalable backend services and REST APIs using Node.js, Express.js, TypeScript, and PostgreSQL, sustaining 99% uptime in B2B production environments. - Built data ingestion pipelines to consolidate and process unstructured data from disparate sources, integrating results with React.js and React Native frontends. - Deployed cloud infrastructure with CI/CD pipelines via GitHub Actions for automated, reliable deployment workflows. - Collaborated across timezones with a remote team, mentoring junior engineers and communicating progress clearly to business stakeholders.

  • Software Engineer at Neptunemm
    Apr 2021 - May 2023 · 2 yrs 2 mos

    - Designed RESTful APIs for data processing, authentication, and third-party integrations using JWT and Redis caching, improving performance by 60%. - Built microservices architecture to decouple a monolithic system, improving scalability by 40% and reducing deployment time by 30%. - Integrated backend services with React.js and React Native frontends with real-time WebSocket updates, reducing data latency by 40%. - Delivered responsive UI for a platform serving 10,000+ users using React.js, Tailwind CSS, and Redux state management. - Managed AWS infrastructure (EC2, S3, IAM, CloudWatch) across dev, testing, and production environments. - Worked in Agile sprints with code reviews, Git version control, and CI/CD pipelines.

  • Software Engineer Internship at BizLeap Technology
    Feb 2019 - May 2019 · 4 mos

    • Assisted in developing HR management software features including employee profiles, leave tracking, and payroll modules, using Java and SpringBoot for functionality. • Created high-fidelity UI/UX designs in Adobe XD and translated them into responsive, functional frontend components. • Developed comprehensive unit testing suites using JUnit, ensuring high software reliability and significantly reducing production bugs. • Supported database design and optimization using MySQL, implementing normalized schema and efficient queries