Frontend Software Engineer

Pattarapon Siwapornchai

I've been building web and mobile apps for over 5 years, mostly in Angular, React and TypeScript. I care about fast pages, accessible UI, and components a whole team can reuse.

See my work Get in touch

GitHub LinkedIn Resume (PDF)

About

Portrait of Pattarapon Siwapornchai

Hi, I'm Thay. I'm a frontend engineer based in Massachusetts, and I build large-scale applications in Angular, React, and TypeScript.

Over the last 5+ years I've shipped everything from React Native apps for agency clients to enterprise Angular platforms used by tens of thousands of people. The work I enjoy most is the foundational stuff: performance, accessibility (WCAG), and component libraries that let a whole team move faster.

I also set frontend coding standards, review a lot of pull requests, and mentor newer developers. Lately I've been using spec-driven development with AI coding assistants to ship features faster without letting quality slip.

Skills

Languages
TypeScript, JavaScript, HTML, CSS, SCSS
Frameworks & libraries
Angular, React, Next.js, RxJS, Redux Toolkit, React Native, Tailwind CSS, PrimeNG, Express
Testing & tools
Jasmine, Jest, Node.js, npm, Git, GitHub, Bitbucket, Postman, Jira, Amplitude
Practices
Accessibility (WCAG), performance optimization, component libraries and design systems, CI/CD, AI-assisted and spec-driven development

Experience

Software Engineer II, Frontend

Advisor360 · Apr 2022 to present

  • Lead frontend development of Angular/TypeScript modules for an enterprise wealth-management platform serving 30,000+ financial advisors, driving architecture decisions around performance, accessibility (WCAG), and modular design.
  • Spearheaded refactoring of legacy UI into a shared component library adopted across multiple teams, improving UI consistency and reducing duplicate code.
  • Cut build times and reduced rendering overhead by migrating key components to OnPush change detection and lazy-loading feature modules.
  • Code owner for core application areas: established frontend coding standards, reviewed pull requests, and mentored junior developers.
  • Adopted spec-driven development with AI coding assistants, turning detailed specs into implementation plans, generated code, and unit tests, then reviewing output against team standards.
  • Authored design documents for new features with backend engineers and UX designers, and partnered with QA on test strategy (Jasmine/Jest).

Junior Software Developer

Trout House Tech · Aug 2021 to Mar 2022

  • Built reusable React and React Native component sets shared across multiple client projects, speeding up delivery of new apps.
  • Implemented key features like Authentication (Google, Apple), state management with Redux Toolkit, and database management with Firebase.
  • Translated Figma designs into responsive, production-ready UIs.

Education

Projects

OYA

Split shared expenses with friends. Invite people to a group, log what you spent, and OYA works out group and individual totals.

Next.js, NextAuth, Framer Motion, MongoDB

Code on GitHub

Sandbox

A catalog of free learning resources for educators and parents, with authentication and authorization via Passport.js.

Node, Express, EJS, Passport, MongoDB

Code on GitHub

Not-Spotify

Built with John Raymond and Patrice Brooks. Search music through the MusixMatch API and make your own playlists, with bcrypt-secured accounts.

React, Express, bcrypt, MongoDB

Code on GitHub

Smaller projects

Quiz Game

Dynamically generated questions for learning.

Live Code

Tic-Tac-Toe

Win detection and reset, in jQuery.

Live Code

Dad Joke Generator

Fetches jokes from icanhazdadjoke with Axios.

Live Code

Contact

Want to talk frontend architecture, accessibility, or design systems? Or just say hi? Send me a message here or email me directly.

pattasiwa@gmail.com