Software Engineer (SY-BI-SW-2026-175-LD)

About the role

CERN is a major European research organization dedicated to advancing the understanding of fundamental physics through large-scale scientific experiments. The Software Engineer position designated as SY-BI-SW-2026-175-LD is a contract appointment based at CERN's facilities in Geneva, Switzerland. The person in this role will apply software engineering principles to support the computing and data analysis needs of CERN's research programs, working alongside scientists and engineers to develop and sustain software systems used in particle physics research. The work contributes to the broader goal of enabling discoveries in high-energy physics through reliable and efficient software solutions. CERN's work spans a wide range of computing challenges, from real-time data acquisition to long-term archival and analysis platforms.

Key facts

What you'll do

• Write and review source code for applications used in scientific computing and data analysis at CERN
• Participate in the full software development lifecycle from requirements gathering through deployment and maintenance
• Collaborate with physicists and other engineers to understand computational needs and translate them into functional software
• Debug and resolve issues in existing software systems to ensure stable and correct operation
• Contribute to the design of software architecture for tools that process large volumes of experimental data
• Document software functionality, usage patterns, and internal design decisions for future maintainers
• Integrate third-party libraries and frameworks into CERN's software ecosystem where appropriate
• Support the testing and validation of software releases before they are deployed to production environments
• Work within version control systems to manage code changes and coordinate with team members on shared projects
• Attend meetings and discussions to provide updates on development progress and to receive feedback from stakeholders
• Refactor legacy code and improve existing software to increase performance and maintainability of critical systems
• Participate in code reviews to ensure adherence to coding standards and to share knowledge across the engineering team

Requirements

• Demonstrated experience in software engineering with a focus on building and maintaining functional applications that meet user needs
• Familiarity with programming languages commonly used in scientific and research computing environments is expected for this role
• Understanding of software development practices such as code review, testing, and version control is essential
• Ability to work effectively in a team setting with diverse technical and scientific backgrounds from around the world
• Strong written and verbal communication skills are needed for documenting work and collaborating across research groups
• A degree in computer science, software engineering, or a closely related technical field is required
• Prior experience working in a research or laboratory environment is valued and considered an advantage
• Willingness to learn new tools, frameworks, and domain-specific knowledge as projects and needs evolve over time
• Experience with agile or iterative development methodologies is beneficial in a fast-paced research environment
• Comfort with ambiguity and the ability to adapt priorities as research directions evolve over time

Nice to have

• Prior experience with software used in physics experiments or high-performance computing contexts is a strong advantage
• Familiarity with distributed computing systems and large-scale data processing pipelines is beneficial for this role
• Knowledge of continuous integration and continuous delivery practices for software releases helps maintain code quality
• Experience mentoring junior developers or contributing to open source software projects demonstrates initiative and collaboration
• Awareness of data security and privacy considerations when handling sensitive research information is a plus

Skills & tools

• Proficiency in one or more general-purpose programming languages used for application development
• Experience with version control systems for managing and tracking code changes across teams
• Familiarity with debugging and profiling tools for identifying performance issues in software
• Understanding of operating systems and their role in running scientific computing applications
• Knowledge of software testing frameworks and methodologies for ensuring code quality and reliability
• Ability to work with documentation tools and technical writing standards for clear communication

Practical notes

• This is a contract position, meaning the employment duration is defined by the terms of the agreement rather than being permanent
• The role is based in Geneva, Switzerland, and candidates should be prepared to work on-site at CERN facilities
• Contract roles at CERN may have specific administrative requirements related to international employment and residency arrangements
• The hiring process for this position may involve technical interviews and assessments of coding ability and problem-solving skills

About the company

CERN runs the biggest particle physics lab globally. Founded in 1954, headquarters sit in Meyrin near Geneva, on the France Switzerland border. Membership includes 25 nations. Israel joined in 2013 and resides outside Europe. United Nations General Assembly status is observer. Scientific exploration drives operations. International collaboration defines culture. Roles span engineering, computing, and research. Opportunities attract diverse talent. Ambitions center on advancing knowledge. Work happens at the intersection of theory and experiment, supported by shared infrastructure and open science principles.