Senior Fullstack Developer (Java, ReactJS, AI)

Zalo Business Solution are powerful business solutions that enable enterprises to connect with customers through Zalo Official Accounts and send secure, personalized notifications via Zalo Business Message Template Service, enhancing engagement and communication efficiency.

We build large-scale platforms that serve tens of millions of users. You will work across the full stack — owning both backend services and frontend experiences — and help shape how AI is woven into the engineering process and the products we ship. Strong technical skills matter, but so does the mindset: curiosity, ownership, and a genuine appetite for using AI to move faster and build smarter.

What you will do

• Design and develop high-performance, scalable backend services using Java (Spring Boot);
• Build and maintain microservices, APIs, and platform features serving millions of users;
• Build and maintain responsive, performant frontend interfaces using React and Next.js;
• Own and maintain the business billing system, ensuring high accuracy, reliability, and consistency in financial data processing;
• Use AI coding tools daily to accelerate development, reduce repetitive work, and ship faster across the full stack;
• Build AI-powered toolkits, internal automation, or product features that drive innovation;
• Collaborate with Product, Design, and cross-functional teams to deliver polished, end-to-end user experiences.

What you will need

• 3+ years of full-stack development experience; strong Java backend (Spring Boot) and modern frontend skills;
• Proficiency in React and Next.js — component architecture, SSR/SSG, routing, and performance optimization;
• Solid grasp of OOP, data structures, algorithms, RESTful API design, and Java 8+ (Java 17 or 21 a plus);
• Experience with distributed systems, concurrency, caching (Redis), and SQL/NoSQL databases;
• Familiarity with Linux, Git, CI/CD, and containerization (Docker/Kubernetes);
• Hands-on experience with AI tools (GitHub Copilot, Cursor, Claude, etc.) for coding, debugging, and documentation;
• Ability to use AI effectively and integrate it into day-to-day engineering workflow across both backend and frontend;
• Mindset of continuous experimentation — explores new AI tools and shares learnings with the team.