Software Engineer (Python) (OSI-SIS-TS-2026-185-LD)

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.

Introduction

Join CERN's Scientific Information Service, as part of the OSI Department , and contribute to the development of platforms such as INSPIRE, SCOAP³, CERN Analysis Preservation and HEPData, used by researchers and scientific communities worldwide. You will design, develop, and operate backend applications, APIs, integrations, and data processing workflows, working primarily with Python and Django.

You will also help bring machine learning and emerging AI capabilities to these platforms, including information extraction, classification, matching, recommendation, semantic search, RAG, and LLM-based applications. You will explore new ways of connecting scientific information platforms, including technologies such as the Model Context Protocol, with a focus on production systems rather than fundamental ML research.

Functions

- Develop, maintain, and operate scientific information applications using Python and Django, including APIs, data models, integrations, and data processing workflows.
- Integrate machine learning and AI capabilities into production systems, using technologies such as Large Language Models, retrieval-augmented generation, semantic search, and the Model Context Protocol.
- Evaluate emerging AI technologies and apply them to concrete scientific information use cases.
- Ensure software quality through automated testing, code review, monitoring, and continuous integration.
- Collaborate with software engineers, product owners, and information specialists on technical solutions and architecture.

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

Behavioural competencies

- Achieving Results: delivering high quality work on time and fulfilling expectations.
- Solving Problems: identifying, defining and assessing problems, taking action to address them.
- Learning and Sharing Knowledge: keeping up-to-date with developments in own field of expertise and readily absorbing new information.
- Working in Teams: supporting and acting in accordance with team decisions; accepting joint responsibility for team successes and shortcomings.
- Communicating Effectively: demonstrating a pro-active approach to resolving differences; addressing issues of conflict constructively.

Language skills

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

Requirements

Strong professional experience in Python and software engineering, including backend development with Django or a comparable Python framework, API design, relational databases, and maintainable production software.; Experience with data-intensive applications or data processing workflows.; Good understanding of modern Large Language Model technologies and their integration into software systems.; Experience with Apache Airflow, React and TypeScript, OpenSearch or Elasticsearch would be an asset.; Experience with LLM applications, retrieval-augmented generation, embeddings, semantic search, Model Context Protocol, tool calling, or AI agent integrations would also be an asset.; Development of application software, design, development and maintenance of production software applications, APIs and data processing workflows using Python and Django.; Knowledge of programming techniques and languages, strong knowledge of Python, software engineering principles, API development, relational databases and modern development practices.; Architecture and design of ICT systems, designing maintainable and scalable software architectures, integrations and data intensive applications.; Testing, diagnosing and optimisation of software, applying automated testing, monitoring, debugging, performance analysis, and continuous integration to ensure software quality and reliability.

Benefits

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.