JSON Linked Data (JSON-LD) is a lightweight Linked Data format. It is easy for humans to read and write. It is based on the already successful JSON format and provides a way to help JSON data interoperate at Web-scale. JSON-LD is an ideal data format for programming environments, REST Web services, and unstructured databases.
Within Verifiable Credentials, JSON-LD is used to convert it to a normalized document. Normalization is required for proof generation and validation.