Java API Developer (Consultant)

Talentquanta is seeking a highly experienced Java API Developer to support a strategic development engagement in Luxembourg. The consultant will be integrated into the development team and work closely with a major client’s IT organisation on site, contributing to the design and delivery of secure, vendor-neutral, and cloud-portable applications.

This role is ideal for a senior consultant with strong Java, API, and cloud expertise, accustomed to working in complex enterprise environments.

‍

Key Responsibilities

• Design and develop vendor-agnostic, cloud-portable Java applications
• Develop and maintain back-end services and APIs
• Integrate Spring Boot applications with external services
• Design, develop, and integrate RESTful APIs
• Implement application security and secrets management (e.g. HashiCorp Vault)
• Integrate and configure databases, including schema management tools such as Liquibase
• Containerise applications using Docker, supporting cloud-agnostic deployments
• Manage licensing and compliance constraints of integrated components and dependencies
• Collaborate closely with development teams and client stakeholders
• Produce and maintain technical documentation, analysis documents, and implementation guides

Required Expertise

• University degree in IT or equivalent professional experience
• 15+ years of professional IT experience
• Strong expertise in Java (8–21) and Spring Boot
• Proven experience designing and integrating RESTful APIs
• Solid background in backend development, testing, and troubleshooting
• Experience with SQL and common data formats (JSON, XML, HTML)
• Hands-on experience with Maven and dependency management
• Experience working in cloud environments (AWS, Azure, GCP) and SaaS/CaaS
• Knowledge of containerisation using Docker and cloud-agnostic deployments
• Experience with application security, including secrets management (e.g. HashiCorp Vault)
• Familiarity with Kafka and event-driven architectures
• Experience with CI/CD pipelines, Git-based delivery, and Agile/Scrum
• Exposure to monitoring and logging tools (e.g. ELK stack)
• Experience documenting solutions in enterprise environments
• Excellent command of English and good knowledge of French

Engagement Details

• Long-term consultancy assignment
• Based in Luxembourg with on-site presence required
• Enterprise-scale, API-centric development environment

‍