Assessment of Transversal Skills in STEM (ATS STEM) is an innovative policy experimentationproject, which aims to enhance digital assessment of students’ transversal skills in STEM. ThisErasmus+ project is situated in primary and secondary schools across eight European countries,involving 12 partners on different levels of educational system.Teachers and researchers havecollaboratively developed and piloted several integrated STEM learning activities all focusing onUNsustainable development goals. Embedding formative digital assessment of STEM learners’work has been a central component. This paper provides an overview of the project and shares someresults from Sweden and Ireland. We provide examples from practice that help illustrate thecomplexitywith a particular focus on technology education.