We show an approach how to provide computed feedback on citizens’ proposals based on open data and expert knowledge in urban planning and public participation by using Domain-Specific Languages (DSL). We outline the process involving different stakeholders of engineering such a DSL and provide an architecture capable of executing the language and uploading new scripts at runtime. A real-world example of the city of Hamburg is used to show the principles and serves as input for development. A prototype has been implemented and evaluated at various events involving citizen and city representatives. We conclude that DSLs can be successfully applied to enable a new way to access data in a more convenient and understandable form, abstracting from technical details and focusing on domain aspects.