JSON Designer is a free app designed for modeling JSON structures with a focus on visualization and design. The app has been available for a couple of years, offering users a smooth design experience and incorporating feedback for improvements. While JSON modeling is the core feature provided for free, code generators are available as a separate paid feature. The app aims to simplify the representation of JSON structures, making it easier for users to define APIs without extensive JSON documentation.

Tree structures in JSON Designer illustrate hierarchical object structures, while multiplicity indicators represent arrays. Users can create, export, and reverse-generate JSON models, access hand-picked API examples, and even generate Protocol Buffers for gRPC. The app also offers tutorials and the ability to exchange JSON files with other applications.