Java Developer - Remote Backend Engineer for Payments Platform

About the Role

We are hiring a Java Developer remote to join Sertis, a leading Data and AI engineering firm based in Bangkok, Thailand. This fully remote position allows you to work under US time zones, contributing to the development of backend services for our payments platform. As a Java Developer, you will play a crucial role in building scalable, secure, and reliable services that drive our innovative solutions.

What You'll Do

• Develop, refactor, and maintain Java-based backend services using Java (Java 8 to 21).
• Build and maintain RESTful APIs and service integrations.
• Write clean, maintainable, and production-ready code aligned with engineering standards.
• Work with frameworks such as Spring Boot within a microservices architecture.
• Participate in code reviews and contribute to improving code quality and team practices.
• Troubleshoot and resolve production issues with a focus on system stability.
• Collaborate with Product, Security, and QA Engineers to support testing and fix defects promptly.
• Contribute to system design discussions, including scalability, performance, and reliability.

Requirements

• 2–4 years of professional experience as a Java Developer or Backend Engineer.
• Great understanding of Java, with the ability to work with legacy systems (Java 8) while migrating to modern versions (Java 21).
• Solid understanding of modern Java features such as Lambda expressions, Stream API, and Functional programming concepts.
• Experience with Spring or Spring Boot frameworks.
• Familiarity with relational databases and SQL; experience with JPA/Hibernate is a plus.
• Strong understanding of object-oriented design principles and common design patterns.
• Experience building backend systems, APIs, and distributed services.
• Strong English communication skills, both written and spoken.

Nice to Have

• Experience with messaging systems such as Kafka or RabbitMQ.
• Exposure to cloud environments (AWS, GCP, or similar).
• Experience working in high-availability or high-transaction systems, ideally in fintech or payments.
• Experience with performance tuning and system optimization.

What We Offer

• Fully remote position (work from anywhere under US time zones).
• Opportunity to learn modern Java practices on a real migration project with senior mentorship.
• Collaborative and supportive team environment.