Junior Software Engineer

What you'll do

Are you interested in building reliable, large-scale control and data systems for one of the world’s most complex scientific machines? In this role, you will contribute to the redesign and deployment of the LHC Post-Mortem system, a critical infrastructure used to analyse and understand machine events such as beam losses, magnet quenches, and beam dumps. You will work on the evolution of the system towards a modern, scalable architecture based on streaming technologies, long-term data storage, and containerised services, ensuring high performance, reliability, and readiness for future LHC operation. As part of CERN’s Machine Protection and Electrical Integrity Group, you will collaborate closely with engineers, physicists, and operations teams to support safe and efficient accelerator operation during Run 4 and beyond.

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Your responsibilities

Develop and maintain robust Java services (using Spring Boot) and client libraries (Java and C++) based on the existing PM system code, ensuring high reliability and maintainability.
Leverage DevOps practices to automate deployment, monitoring, and scaling of the new system in a Kubernetes environment.
Create comprehensive test suites to validate the system's functionality and performance under real-world scenarios and throughput requirements.
Implement a data migration solution to transition from the legacy Oracle-based storage to the new long-term storage.
Collaborate closely with stakeholders and system clients to understand and meet their requirements, ensuring seamless integration with existing workflows.

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Your profile

Experience with Java back-end development, Kubernetes and DevOps practices
Working knowledge of Scrum/Kanban methodologies
Strong aptitude for understanding large codebases and refactoring for improved maintainability
Your studies focused on Computer Science or Software Engineering

Your skills

Java (Spring Boot), C++
Understanding of concurrency and multithreading
Networking knowledge
Familiarity with relational databases
Basic Kubernetes and Apache Kafka knowledge
Familiarity with DevOps (CI/CD, IaC, monitoring)
Ability to work effectively in a team and participate in design discussions
Spoken and written English, with a commitment to learn French

Ideal start date: 01/04/2026

Contract duration (in months): 24

Job flexibility: Fully Onsite

Global Benefits at CERN

A monthly stipend between 5266-5793 Swiss Francs per month (tax free) depending on your degree.
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 and travel expenses) depending on your individual circumstances.
Possibility to extend your contract up to 36 months.
On-the-job and formal training including language classes.

Let's get you ready

Be sure to meet the eligibility criteria

You are a national of a CERN Member State or Associate Member State.
By the application deadline, you have a maximum of 2 years of professional experience since graduation in the respective field and your highest educational qualification is either a bachelor’s or master’s degree. You must have a university degree and can’t hold a PhD.
You have never had a CERN fellow or graduate contract before.
Please pay attention to the additional criteria and requirements for this specific position and mentioned above.

You will need these documents to complete your application

Your CV (English or French)
Any document you consider relevant to your application
A copy of your most relevant diploma or a certificate of achievement from your school (if you don't yet have your paper diploma)

Your CERNDepartment

The TE department specializes in maintaining world-class expertise in accelerator technologies, supporting R&D, and managing technical facilities to advance CERN's technological capabilities.

Overview of CERN

Discover a world where the impossible is made possible!

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!

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Still have a doubt ? Here are the most frequently asked questions

What should I expect during my first week at CERN?

Your onboarding at CERN includes a comprehensive induction programme, which starts with an official welcome session at the beginning of each month. In addition, you will receive important information both before and after your arrival to ensure a smooth transition into your new role. This process is designed to help you get acquainted with CERN’s environment, your team, and the tools and systems you’ll be using.
How big would the team be?

The size of the team you'll be working with at CERN depends on the specific role and department. Some teams are small and highly specialized, while others are larger and more interdisciplinary. During the interview process, you'll have the opportunity to learn more about the team structure for the position you are applying for.
What is the working language at CERN?

The working languages at CERN are English and French. However, it is not always mandatory to speak both languages to work at CERN. We offer language training to help you acquiring the other language.
What support does CERN provide for relocation?

CERN does not offer direct assistance with relocation. However, depending on your role and specific criteria, you may be eligible for certain benefits such as an installation allowance and coverage of travel expenses to join CERN. These benefits are designed to help ease the transition when relocating to the Geneva area. For more information, please consult the “Salary, Benefits and Support“ page.
Do I need a visa to work at CERN?

Whether you need a visa to work at CERN depends on your nationality and the duration of your stay. CERN assists with the necessary visa and work permit processes for its employees and visitors. The specific requirements will be communicated to you during the recruitment process.
What would my salary be?

Salaries at CERN are determined by a structured scale. Salaries are based on your role, qualifications, and experience, and are not subject to negotiation. Specific details will be provided as your application progresses. For more information, please refer to the dedicated page.