Senior Fullstack Engineer (NodeJS, ReactJS)

Role Overview

• As an early senior engineer on the project, you'll work on a greenfield product and have the opportunity to contribute across frontend, backend, and AI-powered features. You'll work directly with the client's technical founder and collaborate closely with the engineering team to turn ideas into reliable, production-ready solutions.

• This is a hands-on opportunity for a strong Senior Fullstack Engineer who enjoys working independently, solving technical problems, and building modern products from the ground up.

What You'll Do

• Build and maintain product features across frontend, backend, APIs, and data using React.js, TypeScript, Node.js, and PostgreSQL.

• Develop AI-powered features using LLM APIs, including prompt design, tool/function calling, streaming, structured outputs, and error handling.

• Build reliable AI workflows with a focus on quality, performance, scalability, and cost.

• Contribute to application design and make practical technical decisions that support maintainability, performance, and scalability.

• Work with a flexible AI/LLM integration approach, allowing different models or providers to be introduced as the product evolves.

• Take features from technical implementation through production, balancing development speed with code quality and maintainability.

• Use Claude Code and modern AI development tools as part of your day-to-day engineering workflow.

• Work directly with the client's technical founder to clarify requirements, discuss technical solutions, and deliver high-quality features.

• Participate in code reviews, technical discussions, and knowledge sharing, and help mentor junior engineers as the team grows.

Who We're Looking For

• 5–7+ years of professional software engineering experience, with strong fullstack experience.

• Strong hands-on experience with React.js / TypeScript and Node.js / TypeScript.

• Solid experience with PostgreSQL, database design, and backend/API development.

• Experience building and maintaining production-grade web applications.

• Hands-on experience integrating LLM APIs into real applications, beyond using AI tools for coding.

• Practical experience with prompt design, tool/function calling, streaming, structured outputs, and LLM error/cost handling.

• Understanding of how to integrate different AI models or providers in a maintainable way.

• Experience using Claude Code or similar AI coding agents in your development workflow.

• Comfortable working independently, breaking down requirements, troubleshooting problems, and taking ownership of assigned features.

• Able to communicate technical solutions clearly and collaborate effectively with international stakeholders.

• Strong spoken English and confidence participating in technical discussions.

Why Join Us

• Greenfield product: Build a new AI product from the ground up instead of maintaining a legacy system.

• Hands-on AI experience: Work on real AI-powered features and modern LLM technologies.

• Real product ownership: Take ownership of meaningful features from development through production.

• Global collaboration: Work directly with international technical leadership in an English-speaking environment.

• Growth opportunity: Join early, work closely with experienced technical stakeholders, and grow with the product and engineering team.

What We Offer

• Attractive and competitive performance-based compensation package.

• Full gross salary during probation.

• 13th-month salary and dedication bonus.

• Comprehensive healthcare insurance and annual health check-ups.

• Flexible check-in time before 10:00 AM on weekdays.

• 2 days of remote work per week.

• 12 annual leave days, 5 sick leave days, public holidays in accordance with Vietnamese Labor Law, plus an additional Christmas day off.

• Opportunity to work on global projects and international teams.

• Daily breakfast and Happy Thursday gatherings.

• Active sports and interest clubs, including badminton, running, football, and music.

• Team-building activities, annual company trips, and year-end celebrations.

• Continuous learning through technical and soft-skills training, English classes, and internal communities.

• Financial support for important life events, including marriage, childbirth, and bereavement.