SeatOS is on a mission to transform and digitize the land & sea travel industry, making all routes instantly bookable by anyone. Part of the leading land & sea transportation group, Travelier, SeatOS is building the dominant Transport Management System (TMS) in APAC.

We are hiring a Senior Frontend Developer (React) to join our growing team in Thailand. This is a hands-on engineering role focused on building high-performance, scalable UI for our core product. You’ll work closely with Product, Design, and Backend Engineering to bring great ideas to life, and play a key role in shaping our frontend architecture and engineering culture.

This role is full-time and will be based in Thailand (remote or hybrid options available).

Responsibilities will include:

• Build and maintain complex, production-grade frontend applications using React, TypeScript, and modern tooling.
• Collaborate closely with Product Managers, Designers, and Backend Developers to deliver end-to-end features with a high level of quality and polish.
• Lead architectural discussions and make technical decisions related to frontend tooling, performance, and scalability.
• Write clean, modular, and testable code that adheres to best practices in frontend development.
• Improve UI performance, reliability, and accessibility across browsers and devices.
• Contribute to and evolve our design system, ensuring consistent and reusable components.
• Mentor junior and mid-level developers, setting a high standard for code quality and peer review.

• 4+ years of professional experience building modern web applications.
• Deep expertise in React, TypeScript, HTML, CSS, and component-driven architecture.
• Hands-on experience with state management libraries such as Redux, Zustand, or React Query.
• Strong understanding of frontend performance optimization and accessibility best practices.
• Familiarity with modern design systems or libraries like Tailwind, MUI, or Chakra UI.
• Experience with unit and integration testing using frameworks such as Jest or React Testing Library.
• Comfortable working autonomously in a fast-paced, high-growth startup environment.
• Strong communication skills and a team-first mindset.