About the Role

RMT Labs is a Luxembourg-based AI company and Recognised Private Research Institution, founded in 2022. It builds European AI models, provides expert AI and engineering teams to enterprises, financial institutions and public-sector organisations, and develops its own AI products, including Skillbourg, an AI-powered recruitment and HR lifecycle platform. As a Senior Java Developer, you will own the design and delivery of backend systems that turn AI research into production software, building scalable and secure Java 17+ and Spring Boot microservices for Skillbourg and client engagements with banks and EU institutions. You will work closely with the CTO, AI engineers, the product team and clients, help shape engineering standards as the company grows, and work fully remotely with hours overlapping with Central European Time, with occasional planned trips to Luxembourg for team events or client meetings. RMT Labs does not offer visa sponsorship or relocation support. You must already have the right to work in the country you will work from.

Key Responsibilities

• Design, build and maintain backend microservices in Java 17+ and Spring Boot for Skillbourg modules including company and candidate profiles, job postings, the applicant tracking system and messaging
• Build and maintain integrations with job boards, HR systems and partner platforms, including job distribution, candidate data synchronisation and webhooks
• Design versioned REST APIs using OpenAPI and implement event-driven workflows with Apache Kafka for processes such as application status changes, notifications and candidate ranking updates
• Integrate AI models and LLM services into Java applications, working on inference APIs, evaluation logging, monitoring, audit trails, explainability data and human-in-the-loop controls that support GDPR and EU AI Act obligations
• Deliver Java and Spring Boot solutions for enterprise, banking and EU-institution clients, contribute to technical workshops, estimate work and translate business requirements into technical designs
• Lead technical design, review code, mentor junior and mid-level developers, and improve quality, security and operations through testing, secure coding, containerisation, Kubernetes deployments, CI/CD, Infrastructure as Code, observability and incident follow-up

Requirements

• 6+ years of professional backend development with Java, including recent hands-on work with Java 17 or later
• Deep experience with Spring Boot and the Spring ecosystem, including Spring Web, Spring Data JPA or Hibernate, and Spring Security
• Experience designing and running microservices in production, including REST API design, event-driven messaging with Apache Kafka or a similar broker, and strong SQL skills with PostgreSQL or another relational database
• Hands-on experience with Docker, Kubernetes, CI/CD pipelines such as GitLab CI, GitHub Actions or Jenkins, and at least one major cloud platform: Azure, AWS or Google Cloud
• A testing mindset and solid knowledge of clean code, design patterns, domain-driven design, security and data protection, including OAuth2, OpenID Connect and GDPR-compliant handling of personal data
• Clear communication with technical and non-technical stakeholders, experience mentoring other developers, fluent English at C1 level or above, and a bachelor’s degree in Computer Science or a related field, or equivalent professional experience

Nice to Have

• Experience with Redis and Elasticsearch or OpenSearch
• Experience integrating LLMs or ML models into Java applications, including Spring AI, LangChain4j, OpenAI-compatible APIs or vector databases such as pgvector
• Experience in regulated environments such as banking, financial services or EU institutions
• A background in HR tech, recruitment, marketplaces or search and matching systems
• Familiarity with the EU AI Act, ISO 27001 or similar compliance frameworks
• French, German or Romanian

Skills we're looking for

Technical skills

• Java
• Spring Boot
• Microservices Architecture

Interpersonal skills

• Stakeholder Management
• Cross-Functional Collaboration
• Business Acumen