Backend Python Engineer

What you'll do

You will join the Tools and Services section within the Scientific Information Service, the team responsible for the platforms that power scientific discovery and open access across the High Energy Physics community. Our systems include INSPIRE, the global literature hub for particle physics; SCOAP3, which funds and tracks open access publishing; CERN Analysis Preservation, which safeguards the analyses behind physics results; and a tool facilitating access to CERN’s institutional memory.

As a Backend Python Engineer you will design, build and operate the services that ingest, curate, search and expose millions of scientific records to a worldwide audience. You will work on high throughput data pipelines, REST APIs, search infrastructure and the integration of AI driven retrieval into production systems. Your code will be open source and used daily by researchers across hundreds of institutes.

As part of the Tools and Services team, you will drive the modernisation and evolution of the Scientific Information Service content platform. You will advance the backend services behind INSPIRE, SCOAP3 and CERN Analysis Preservation, expand Model Context Protocol services that open the team’s scientific content to AI clients, and evaluate the harmonisation of the INSPIRE backend with the newer backoffice stack. This is a defined project to strengthen the platform’s discovery, interoperability and AI driven access.

Your responsibilities

The core responsibility of this position is to drive the modernisation of the INSPIRE backend, expand the team's Model Context Protocol services, and align the digitisation and archival services with the team's technology stack, delivering a large scale migration to the Access to Memory (AtoM) service.
Review the remaining custom harvests, approximately 1000, and migrate those that should be retained to Apache Airflow, retiring or redesigning the rest.
Work with curators throughout to decide what to keep, and automate the pipeline where evaluation shows it adds value, keeping a human in the loop for decisions that require expert judgement.
Evolve the Apache Airflow ingestion and curation pipelines that process scientific metadata and full text at scale, improving data quality, deduplication, enrichment and source coverage.
Expand the team's Model Context Protocol services across INSPIRE, the library and other team services, moving them from pilot to a consistent, documented and maintainable interface that opens curated scientific content to external AI clients.
Develop and optimise the search and discovery functionality on OpenSearch that underpins these features, including relevance tuning and indexing strategies.
Align the digitisation and archival services with the team's technology stack, modernising them onto common frameworks and deployment tooling.
Deliver and oversee the migration of 35 000 new archival items to the Access to Memory (AtoM) service across 2027, maintaining consistent metadata and data quality throughout.
Develop and automate the connection between the connected services, enabling content to flow reliably across the digitisation and archival systems.
Prepare the ingestion pipelines for new file ingestion, harmonising them with the team's other applications.
Design, document and deliver REST APIs consumed by internal applications, partner institutes and third party tools.
Apply automated testing, code review, monitoring and CI and CD, and support production through containerised deployments and performance tuning.
Contribute the team's outputs back to the open source community to advance Open Science.

Still here? Let's make a quick check about

Your profile

Demonstrated experience building and operating backend services in Python in a production environment. Solid track record with web frameworks such as Django, Flask or FastAPI and with relational and document databases.
Hands on experience designing REST APIs.
Practical experience with search engines such as OpenSearch, including indexing and relevance tuning.
Familiarity with containerised deployments, version control with Git and CI and CD workflows.
Experience contributing to open source projects and working in a collaborative engineering team is highly valued.
Your studies focused on Computer Science.

Your skills

Strong proficiency in Python and modern backend development practices, including frameworks such as Django, Flask and FastAPI.
Solid understanding of REST API design, asynchronous programming and software testing.
Experience with SQL data stores such as PostgreSQL and with search technologies such as OpenSearch.
Working knowledge of Docker, Kubernetes and CI and CD pipelines.
Understanding metadata standards and large scale data processing.
Ability to write clean, well documented and maintainable code.
Strong problem solving skills and attention to detail.
Ability to work in a multicultural team and a collaborative, ownership driven mindset.
Spoken and written English, with a commitment to learn French.

Ideal start date: 01/11/2026

Contract duration (in months): 24

Job flexibility: Hybrid

Global Benefits at CERN

A monthly net stipend between 6372-7004 Swiss Francs per month 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. Currently, we cannot consider applications from Pakistani and Lithuanian nationals for positions with a 2026 start date, as the ceiling defined under Article II.5 of the Associate Membership Agreement has been reached.
By the application deadline, you have a master’s degree with 2 to 6 years of professional experience since graduation or a PhD with a maximum of 3 years of professional experience since graduation. You are not eligible with only a bachelor’s degree.
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)
A copy of your most relevant diploma or a certificate of achievement from your school (if you don't yet have your paper diploma)
Any document you consider relevant to your application

Your CERNDepartment

The OSI department is a transversal service provider aiming to increase efficiency, resilience, openness and sustainability. It provides expert guidance on continuous improvement, risk and crisis management, service and process optimisation, and scientific information management, and coordinates CERN’s open science, preservation, and sustainability efforts.

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!

Ready To apply?

Be prepared with our resources and tips

All good?

Apply now Allow 15 minutes to complete your online application

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.