Senior Java and Kotlin Engineer(Contractor)

This is us

At Avenga, we believe that human creativity empowers technology that matters. Operating globally, our 6000+ specialists provide a full spectrum of services, including business and tech advisory, enterprise solutions, CX, UX and Ul design, managed services, product development, and software development.

This is the job

We are looking for Senior/Principal Engineer with strong knowledge in Java and Kotlin, available for minimum 50%. The goal is to build a unified, scalable ads platform.

We are transforming a long-standing business application into a modern technology stack. Our goal is to build a modular monolith designed for scalability and future microservices separation. We follow hexagonal architecture and Domain-Driven Design (DDD) principles to ensure clean, maintainable solutions.

This is you

• Strong experience with modern Java & Kotlin
• Expertise in REST APIs and various authentication workflows (key-based, OAuth)
• Knowledge of relational (PostgreSQL preferred) and non-relational databases (MongoDB preferred)
• Cloud development skills (GCP preferred)
• Experience with Docker, Kubernetes (nice to have)
• Ability to build scalable, high-performance services in a cloud environment
• Experience integrating with Meta and TikTok (nice to have)
• AdTech experience is a strong asset
• English on C1 level

This is your role

• Work with modern Java (17+) and Kotlin
• Collaborate on refactoring legacy code with a focus on quality and maintainability
• Write clean, testable code following SOLID and Clean Code principles
• Create and maintain unit and integration tests
• Cooperate with the front-end team to define API contracts
• Share knowledge within a team of 4 back-end developers and take ownership of your work

What awaits you at Avenga?

At Avenga, everyone matters. We provide equal opportunities in recruitment, career development, and leadership, regardless of race, ethnicity, gender identity, sexual orientation, disability, age, religion, or any other characteristic. We are committed to fostering a work environment where our diverse community of employees, candidates, and business partners actively shapes our growth. By bringing together people from different backgrounds and experiences, we build a workplace where everyone feels free to be themselves while honoring the boundaries of others.