Backend Software Engineer - Database Systems (Oracle/Java) (BE-CSS-IDE-2026-82-LD)

You will design and evolve complex data models at the heart of CERN's accelerator control systems , working on the database backend of large-scale, mission-critical applications. Your work will focus on Oracle-based schemas and Java backend services exposing APIs to applications, tightly integrated into full-stack software systems.

Robust and scalable database systems are essential for control, configuration, and operational applications enabling the operation of CERN's accelerator complex. You will contribute to the evolution of these data-intensive systems, working on long-lived data models and performance-critical access patterns.

You will join a multidisciplinary team and play a key role in building reliable backend solutions aligned with users' needs, contributing to systems used at the world's largest particle physics laboratory.

Functions:

• Interact with stakeholders, including end-users, Product Owners, and infrastructure providers to gather requirements.
• Design and implement reliable data models ensuring ACID properties.
• Develop and maintain APIs to access and manipulate data using CRUD operations, including interfacing with AI systems.
• Analyse integration requirements across multiple technical domains and design and implement robust solutions.
• Contribute to all phases of the software development lifecycle, from requirements analysis to deployment.
• Provide technical supervision and mentoring to junior software engineers.
• Provide day-to-day operational support to a large user community (500+ users).
• Propose and contribute to the evolution of systems under your responsibility and beyond, * Work during nights, Sundays and official holidays, when required by the needs of the Organization.

Master's Degree or equivalent relevant experience in the field of Computer Science or a related field

Experience:

• Experience developing high-performance relational databases with Oracle and/or PostgreSQL RDBMS.
• Experience in the design and evolution of data models in technical domains.
• Knowledge of designing and maintaining high-availability, client-oriented APIs, ideally REST- and gRPC-based.
• Experience in Java software development using Spring Boot, JPA, and Hibernate.
• Application of software quality assurance practices and associated tools.
• Use of CI/CD solutions to build, test, and deploy software to production.
• Practical experience in the use of PL/SQL is an advantage.

Technical competencies:

• Knowledge of programming techniques and languages.
• Design of databases/repositories.
• Architecture and design of ICT systems.
• Identification and selection of relevant emerging ICT technologies.
• Conceptualising, designing and developing user experiences and interfaces.

Behavioural competencies:

• Demonstrating Accountability: working conscientiously and reliably; delivering on promises.
• Achieving Results: delivering high quality work on time and fulfilling expectations.
• Working in Teams: contributing to promoting a positive atmosphere in the team through an optimistic and constructive attitude; addressing issues.
• Solving Problems: adopting a pragmatic approach; understanding the value of adopting generic rather than "gold -plated" technical solutions.

Language skills:

Spoken and written English, with a commitment to learn French.

• A competitive salary (tax free), increasing in line with your years of relevant experience.
• 30 days of paid leave per year plus 2 weeks annual closure.
• Coverage by CERN's comprehensive health insurance scheme (for yourself, your spouse and children), and membership of the CERN Pension Fund.
• Family, child and infant monthly allowances depending on your individual circumstances.
• A relocation package (installation grant, removal, travel expenses) depending on your individual circumstances.
• Possibility to extend your contract up to 8 years + eligibility for indefinite contract tenure.

At CERN , the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. Using the world's largest and most complex scientific instruments, they study the basic constituents of matter - fundamental particles that are made to collide together at close to the speed of light. The process gives physicists clues about how particles interact, and provides insights into the fundamental laws of nature., At CERN, the European Organization for Nuclear Research, we are pushing the frontiers of science and technology. Our groundbreaking work brings together not only physicists but also a diverse range of professionals from engineering, technical, scientific, and administrative fields. Together, we foster an environment where innovation and collaboration thrive. Every day, we face exciting new challenges and opportunities to contribute to cutting-edge research that shapes our understanding of the universe. We meet these challenges through the diverse perspectives within our teams, ensuring every contribution is valued and driving our shared sense of inclusion and purpose. Diversity is a core value of CERN since its foundation, and it remains central to our mission and continued success. If you are ready to be part of a dynamic, inclusive community pushing the boundaries of knowledge, CERN is the place where your curiosity and skills can thrive. Be part of our mission to uncover what lies at the heart of the universe! TAKE PART!