Full Stack Engineer

Job Posting Organization:
CERN, the European Organization for Nuclear Research, was established in 1954 and is one of the world's largest and most respected centers for scientific research. With a mission to uncover the fundamental structure of the universe, CERN employs thousands of scientists, engineers, and support staff from over 100 countries. The organization operates in multiple countries and is known for its cutting-edge research in particle physics, utilizing the world's largest and most complex scientific instruments to study fundamental particles and their interactions. CERN's commitment to diversity and inclusion is a core value, fostering a collaborative environment that drives innovation and discovery.

Job Overview:
The Full Stack Engineer position is an exciting opportunity to work within the Tools and Services team of the Scientific Information Service Group at CERN. This role involves contributing to significant open science platforms such as INSPIREHEP and SCOAP3, as well as developing machine-learning driven systems that enhance the accessibility and usability of scientific data. The engineer will engage in the development of INSPIRE AI, a sophisticated Retrieval-Augmented Generation (RAG) system that utilizes the INSPIRE dataset to deliver accurate answers in high energy physics. The position requires a collaborative approach, working closely with experts across CERN to create platforms that promote discovery and reproducibility in scientific research. The engineer will be expected to adapt to various projects within an agile team, demonstrating flexibility and creativity to meet evolving requirements. Continuous learning and skill enhancement through open-source contributions and tackling unique challenges are also key aspects of this role.

Duties and Responsibilities:
The Full Stack Engineer will be responsible for developing and optimizing the backend of the INSPIRE AI system using Python, LangChain, and FastAPI. They will also contribute to the frontend development using React, ensuring a seamless user experience. The engineer will engage in the design of high-quality scientific paper embeddings and work on robust evaluation methods to ensure the reliability of the system. Additionally, they will collaborate with the CERN IT department and external institutions to design, develop, and deploy innovative tools and services that support thousands of users in the global research community. Regular participation in agile team meetings and adapting to shifting project requirements will be essential. The engineer will also be expected to enhance their skills through formal training and on-the-job learning opportunities.

Required Qualifications:
Candidates must have professional experience in developing and operating production systems, with a strong background in Python and LangChain, particularly in designing retrieval-based AI systems. Experience in integrating AI-driven features into real applications and building modern frontend applications with ReactJS is essential. Familiarity with relational databases, especially PostgreSQL, and the ability to write efficient SQL queries are required. Candidates should have experience collaborating within engineering teams using Git and platforms like GitHub, as well as exposure to multi-component service architectures and MCP servers. A strong understanding of software engineering principles, clean coding practices, and the ability to design and implement features across the full stack are crucial for success in this role.

Educational Background:
The ideal candidate should possess a professional background in Computer Science or a related field. A Master's degree with 2 to 6 years of post-graduation professional experience is required, or a PhD with no more than 3 years of post-graduation professional experience. Candidates must also be nationals of a CERN Member or Associate Member State and should not have previously held a CERN fellow or graduate contract.

Experience:
Candidates should have several years of professional experience in developing and operating production systems. This includes hands-on experience with Python and LangChain, as well as a proven track record in integrating AI-driven features into applications. Experience in building modern frontend applications with ReactJS and working with relational databases is also necessary. Familiarity with Git and collaborative engineering practices is expected, along with exposure to multi-component service architectures.

Languages:
Fluency in spoken and written English is mandatory, and candidates should demonstrate a commitment to learning French. Proficiency in additional languages may be considered an asset but is not required.

Additional Notes:
The contract duration for this position is 24 months, with the possibility of extension up to a maximum of 36 months. The working hours are set at 40 hours per week, and the position is fully onsite at CERN in Geneva. The target start date for this role is March 1, 202

• The job reference number is RCS-SIS-TS-2025-226-GRAP. The compensation includes a monthly stipend ranging from 6287 to 6911 Swiss Francs (net of tax), along with coverage by CERN's comprehensive health scheme and membership in the CERN Pension Fund. Additional benefits may include an installation grant, family allowances, and paid travel expenses at the beginning and end of the contract. Employees are entitled to 30 days of paid leave per year and will have access to formal training and in-house language courses.