A tool for JSON schema witness generation

JSON Schema is an evolving standard for the description of JSON documents. It is an extremely powerful language endowed with boolean operators and recursive definitions. Hence, classical problems like schema consistency and equivalence may be challenging without well-principled tools. Based on our recent effort for laying down an algebraic formal semantics of JSON Schema, we demonstrate an approach for generating valid witnesses of a user-defined schema. Our goal is not only to allow programmers to design schemas that meet their intentions, but also to guide them in their journey to understanding the semantics of existing schemas, in an interactive fashion. We thus aim to contribute to the adoption of the JSON Schema language by facilitating its use.