Full-Stack Software Engineer

Job DescriptionAre you a passionate Full Stack Engineer looking to work in a dynamic and innovative environment? Are you eager to learn and grow in a collaborative and supportive setting? Join our high-performance Tools and Services team within the Scientific Information Service Group, where you will contribute to core open science platforms such as INSPIREHEP , SCOAP3 , and CERN Analysis Preservation , along with machine-learning driven discovery and workflow systems that connect publications, data, and software across high energy physics. You will work on modern, high impact services used by thousands of researchers worldwide and collaborate closely with experts across CERN to deliver platforms that enable discovery, reproducibility, and Open Science. Your responsibilities: Help developing INSPIRE AI, an advanced Retrieval-Augmented Generation (RAG) system that leverages the INSPIRE dataset to provide accurate, source-backed answers in high energy physics. You will help design high-quality scientific paper embeddings, build and optimise the backend with Python, LangChain, and FastAPI, contribute to the React frontend development, and work on robust evaluation methods and metrics to ensure reliability. Engage in a variety of projects as part of an agile team, adapting to shifting requirements and milestones. Your flexibility and creativity will be key in addressing the team's evolving needs. Contribute to the development and operation of various services, which are crucial for supporting thousands of users in the global research community annually. Collaborate with the CERN IT department and other prestigious (external) institutions to design, develop, and deploy innovative tools and services. Regularly enhance your skills and grow your expertise by contributing to open-source projects, addressing unique challenges, and seizing exciting opportunities that align with your engineering interests and strengths. Your profile: Professional experience in developing and operating production systems over several years. Experience with Python and LangChain, including the design of retrieval-based AI systems. Experience integrating or developing AI driven features in real applications. Experience building modern frontend applications with ReactJS. Experience working with relational databases, preferably PostgreSQL, with the ability to write efficient and well-structured SQL queries. Experience collaborating within engineering teams using Git and platforms such as GitHub. Exposure to MCP servers and multi component service architectures. Skills: Strong understanding of software engineering principles and clean coding practices. Ability to design and implement features across the full stack. Understanding of embedding creation and RAG evaluation, combined with a creative and exploratory mindset for improving LLM driven retrieval systems. Strong problem-solving skills and the ability to work effectively within a team. Good understanding of container orchestration concepts, with familiarity in Kubernetes seen as an advantage. Familiarity with search technologies such as OpenSearch or Elasticsearch. Knowledge of continuous integration and deployment practices. Understanding of cloud concepts and infrastructure as code. Spoken and written English, with a commitment to learn French. Eligibility criteria: You are a national of a CERN Member or Associate Member State . You have a professional background in Computer Science (or a related field) and have either:a Master's degree with 2 to 6 years of post-graduation professional experience; or a PhD with no more than 3 years of post-graduation professional experience. You have never had a CERN fellow or graduate contract before. Additional InformationJob closing date: at 23:59. Contract duration: 24 months, with a possible extension up to 36 months maximum. Working hours: 40 hours per week Job flexibility: Fully Onsite Target start date: 01-March-2026 Job reference: RCS-SIS-TS- -GRAP Field of work: Software Engineering and IT Benchmark job: - Computing Engineer What we offer A monthly stipend ranging between 6287  and 6911  Swiss Francs per month (net of tax) . Coverage by CERN's comprehensive health scheme (for yourself, your spouse and children), and membership of the CERN Pension Fund . Depending on your individual circumstances: installation grant; family, child and infant allowances;