Java Backend Engineer (Kotlin) - Temporary

Are you a Senior Backend Engineer looking to leverage your expertise to make a tangible impact on a sustainable future? Our client, a leading renewable energy company based in the vibrant city of Amsterdam, is embarking on a significant technological evolution. They are transitioning their core platform from Scala/ZIO to a modern architecture powered by Kotlin and Spring Boot, and they are seeking a talented Backend Developer to help build this greenfield future. This is more than just a coding role; it's an opportunity to contribute directly to their mission of delivering 100% green energy by developing scalable, high-quality services that underpin their innovative platform. As part of a collaborative, cross-functional team, you will translate complex energy sector challenges into elegant backend solutions, fostering a culture of continuous learning and knowledge sharing. If you're ready to shape the technological backbone of a sustainable energy leader and drive innovation, we encourage you to explore this exciting opportunity!

Responsibilities

What are you going to do?

• Design and build new microservices using Kotlin and Spring Boot;
• Develop and maintain clean, performant APIs for React and React Native frontends;
• Create clean, efficient, and well-documented code with increasing independence;
• Participate in all development stages, including testing, code reviews, and quality assurance;
• Foster a collaborative environment by sharing ideas, feedback, and mentoring other developers.

Requirements

What do you bring?

• Proven senior experience building Kotlin services and a keen interest in API Design;
• Proficiency with Spring Boot or similar JVM frameworks;
• A strong product mindset focused on end-user experience and building from scratch;
• Experience in product-based companies, ideally in cross-functional teams, and a commitment to clean, maintainable code;
• Comfortable communication, bridging technical/business gaps, and using observability tools/metrics to validate features.

Salary and Benefits

Nice temporary assignment in Amsterdam for a sustainable energy company for 32 to 40 hours per week. On this assignment, you will work on a flex contract via our agency. This opportunity is also possible for freelance/zzp.