A user interface (UI) design system mapping platform is provided that can receive and process a design document file and a library file to automatically generate a mapped specification that maps the design document file to the library file. The library file can be generated at a design system and includes design system components for development reuse and their definitions. The design system components can be assembled, via an external design tool, to build user interfaces, applications or layouts. The design document file can be imported from the design tool to the UI design system mapping platform. The design document file is generated based on selected ones of the design system components and includes various design artifacts including layout and assets that describe a user interface of an application.