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.