JSON is a simple language for representing data on the Web. Linked Data is a technique for creating a graph of interlinked data across different documents or Web sites. In Linked Data, “things” are identified using IRIs, which are typically dereferencable and thus may be used to find more information about a particular “thing”, creating a Web of Knowledge. JSON-LD is intended to be a simple publishing method for expressing not only Linked Data in JSON, but also for adding semantics to existing JSON.
The syntax does not necessarily require applications to change their JSON, but allows one to easily add meaning by adding context in a way that is either in-band or out-of-band. The syntax is designed to not disturb already deployed systems running on JSON, but provide a smooth upgrade path from JSON to JSON with added semantics. Finally, the format is intended to be easy to parse, efficient to generate, stream-based and document-based processing compatible, and require a very small memory footprint in order to operate.
Data is messy and disconnected. JSON-LD organizes and connects it, letting your creativity bloom.