Glossary · Semantic web foundations

JSON-LD

Also known as: JSON for Linking Data, JSON-LD 1.1, metadata.jsonld

JSON-LD (JSON for Linking Data) is a W3C standard syntax for writing RDF data as JSON. A context maps JSON keys to IRIs, so ordinary JSON becomes linked data that any RDF tool can read.

Semantic web
Ontology
Information architecture

In one sentence

JSON-LD writes RDF as JSON: a context maps keys to IRIs. iiRDS allows it as metadata.jsonld and requires it for iiRDS/H packages.

Example

The file META-INF/metadata.jsonld in an iiRDS/H package, holding the same metadata as metadata.rdf in a form web developers can read directly.

How it applies

iiRDS: Metadata in JSON-LD 1.1 is stored as META-INF/metadata.jsonld. It is optional for unrestricted iiRDS and iiRDS/A, mandatory for iiRDS/H, and must match metadata.rdf when both exist. The specification notes that RDF/XML may be deprecated in a future version.
Web and SEO: JSON-LD is also the format search engines read for schema.org structured data. Every term page in this glossary embeds a JSON-LD DefinedTerm in its HTML.
Technical documentation: Because it is plain JSON, JSON-LD fits web portals, APIs and JavaScript applications that would never parse RDF/XML.
AI and retrieval: JSON-LD is easy for both code and language models to read, which makes it a practical bridge between semantic metadata and AI pipelines.

JSON-LD vs. JSON

Plain JSON keys only mean something to the application that defined them. In JSON-LD, the @context maps each key to an IRI, so "title" unambiguously means iirds:title — to every consumer.

Example

{
  "@context": { "iirds": "http://iirds.tekom.de/iirds#" },
  "@id": "https://example.com/iirds/io/1312",
  "@type": "iirds:Topic",
  "iirds:title": { "@value": "Mounting the rotor", "@language": "en" },
  "iirds:has-topic-type": { "@id": "iirds:GenericTask" }
}