Scientific Software Developer — Data Reduction Team

ESSE - European Spallation Source ERIC; Lunds kommun; On-site; SEK 650,000 - 900,000; Full time

Benefits offered by this job

25 days annual leave

5 additional days

Pension scheme

Preventative healthcare

Relocation support

Job summary

ESSE - European Spallation Source ERIC is seeking a scientific software developer to join the Data Reduction Team in the DMSC. You will contribute to turning raw detector data into usable datasets, primarily in Python with exposure to C++.

The role spans library development, workflow design, and performance engineering within a collaborative international environment. The team values critical thinking about code quality, ownership, and effective communication.

Qualifications

• Shipped software that real users depend on.
• Think critically about code quality and welcome constructive discussion and alternative ideas.
• Engage with scientific problems; physics background welcomed but not required.
• Take ownership of an area, gather requirements with scientists, and make decisions with incomplete information.
• Comfortable working in English in an international team.

Responsibilities

• Library development and scientific workflow design.
• Performance engineering and optimization of data processing pipelines.
• User interface design and collaboration with scientists.
• Touch multiple parts of the codebase in the first year.

Skills

Python

C++

Software development

English

Team collaboration

Tools

Jupyter

CI/CD

Software architecture

Job description

Reference number ESD-80679

The European Spallation Source (ESS) is building the world’s most powerful neutron source, enabling research in materials science, energy, health, and the environment. ESS is expanding the Data Reduction Team at the Data Management and Scientific Computing Centre (DMSC), located just north of Copenhagen in Denmark. We are seeking outstanding candidates for one scientific software developer position.

About the team

We are six developers responsible for the software that turns raw detector data into scientifically usable datasets. This process, known as data reduction, produces structured datasets for downstream analysis software. We develop Scipp (scipp.github.io) and related libraries, working primarily in Python. With ten new ESS instruments coming online next year, our software will play an important role in supporting their scientific commissioning and operations. As a small team, we work on problems that are both technically challenging and central to the success of the facility.

About the role

The work spans library development, scientific workflow design, performance engineering, and user interfaces. You will work closely with neutron scientists, distil requirements from them, determine what belongs in the core library versus a downstream package, and frequently decide what not to build. There is room to specialize over time, but in your first year you should expect to touch various parts of the codebase.

Our team uses AI coding tools heavily but tries to be smart about it. To us, using AI is about amplifying human thought, not outsourcing it. We see these tools as aids for exploration, iteration, and productivity — not replacements for engineering judgement.

About you

We care more about how you think than which tools you have used. We do not have a fixed technology checklist. What matters:

• You have shipped software that real users depend on.
• You think critically about code quality and welcome constructive discussion and alternative ideas.
• You can engage with scientific problems on their own terms — a physics background is welcome but not required.
• You can take ownership of an area, work with scientists to gather requirements, and make decisions with incomplete information.
• You are comfortable working in English in an international team.

Experience with the scientific Python ecosystem, performance engineering, or work at neutron/photon sources is beneficial but not required. Familiarity with technologies and practices such as Jupyter, C++, CI/CD, integration testing, or systems architecture would also be valuable.

What we offer

DMSC is located on the DTU campus in Kongens Lyngby, north of Copenhagen, while the ESS neutron facility is based in Lund, Sweden. Together, they form a unique cross-border scientific environment in the Øresund region.

You will join a dynamic and highly collaborative international workplace with colleagues representing nearly 60 nationalities across ESS and DMSC. We offer opportunities for professional development, and close interaction between computational science, instrumentation, and large-scale experiments.

Benefits include 25 + 5 annual leave days in addition to public and company holidays, an attractive pension scheme, preventative healthcare benefits, and relocation support for international hires where applicable.

This is a full-time, permanent position based in Kongens Lyngby, Denmark, and we need someone who can start as soon as practically possible.

Learn more about living and working in Scandinavia: https://ess.eu/living-working-scandinavia.

For further information

For information about the position, contact the Group Leader for Research Software Engineering (RSE), Fredrik Bolmsten, at [e-mail]

For recruitment-related questions

Contact Recruitment Officer Janne Erwolter at [e-mail].

How to apply

Please submit your application, with cover letter and CV, no later than 26 August 2026.

As part of your cover letter, please pick one of these two questions and answer it in your application:

• Tell us about a technical decision you made that you would make differently today, and what changed your mind.
• Tell us about a piece of software you admire, not because of what it does, but because of how it is built, and what you learned from looking at it closely.

We’re genuinely interested in your response; it helps us understand your technical judgement and curiosity.

We look forward to receiving your application.