This article asks how pedagogy and technology should be aligned when developing a digital learning design tool. We find that to support student teachers' active learning, the tool must foreground pedagogy. We analysed how researchers, practitioners and software developers jointly developed a tool (ILUKS) that supports student teachers' lesson planning. The tool allows student teachers to collaboratively inquire into planning and improving lessons during practicums. We document the interdisciplinary team's work of co-creation, documentation, feedback and improvement in the development process and conclude that digital tools intended to support students' inquiry-based and active learning must align pedagogical and technical knowledge.