Hiring: Senior Back-End / API Developer (Consultant)

Contract | Onsite Luxembourg

We’re looking for an experienced Senior Back-End/API Developer to join an Agile product team and help design, build, and optimise software tools used to manage complex, large-scale information systems. This role is ideal for someone who thrives in modern Java environments, enjoys solving technical challenges, and can deliver scalable, secure back-end solutions.

Responsibilities:

• Develop robust, portable applications using Java (8–21)
• Build and maintain services using Spring Boot
• Design and implement RESTful APIs; exposure to GraphQL and API gateways (e.g., WSO2)
• Apply strong security practices aligned with SSDF and NIST 800-53
• Manage secrets and credentials with Hashicorp Vault
• Use Maven for dependency and project management
• Work with PostgreSQL, schema management, and Liquibase
• Build cloud-agnostic, containerised applications with Docker
• Integrate and manage event-driven pipelines using Kafka
• Implement and improve CI/CD pipelines and Git workflows
• Conduct testing with JUnit, Mockito, Postman, Testcontainers
• Integrate services on AWS, Azure, or GCP
• Monitor systems using the ELK stack
• Collaborate within an Agile/Scrum framework using Jira, Confluence, SharePoint, and Teams
• Produce technical documentation and installation guides

Experience:

• Bachelor’s degree (or equivalent) in IT, Computer Science, or a related field
• 8+ years of experience in Java back-end development
• Deep expertise in Spring Boot, API development, Docker, Kafka, CI/CD, and cloud platforms
• Strong experience working in Agile teams

If you are a passionate and dedicated IT Professional looking to join a dynamic and innovative organization, we encourage you to apply