JSON-LD

JSON-LD ("JSON for Linking Data") is a way of writing ordinary JSON so a machine can also understand what the fields mean, not just their names. A plain JSON object {"name": "Alice"} doesn't say whether "name" means a person's name, a product's name, or a file name: that meaning lives only in whoever wrote the code that reads it. JSON-LD adds a @context field pointing at a shared, published vocabulary, so "name" in this document means exactly what the referenced vocabulary says it means, anywhere, to any program that bothers to look it up.

JSON-LD is a W3C standard (first published 2014, revised as JSON-LD 1.1 in 2020), developed by the W3C JSON-LD Working Group with Manu Sporny, Dave Longley, Gregg Kellogg, and Markus Lanthaler among its principal editors, largely out of Digital Bazaar. It's built on top of RDF (Resource Description Framework), the much older W3C data model for the "semantic web" that Tim Berners-Lee helped set in motion in the late 1990s. JSON-LD's whole purpose is to let RDF-shaped data travel in a format web developers already use every day, instead of the more academic serializations RDF started with.

Why Verifiable Credentials use it

The W3C Verifiable Credentials Data Model gives issuers two different ways to cryptographically secure a credential: VC-JOSE-COSE (wrap the credential in a signed JWT or COSE structure, no linked-data processing involved) or VC Data Integrity (keep the credential as JSON-LD, and attach a proof block computed over its canonicalized RDF form, see the Data Integrity Proof entry). JSON-LD is what makes the second path possible: the @context array is what lets a credential type mean something precise and dereferenceable, rather than just a string two parties happen to agree on informally.

Solidus status

Solidus's own documentation illustrates its Verifiable Credentials in JSON-LD form, a @context array naming the W3C VC context plus a Solidus-specific one. But the credential format Solidus actually ships and serves live today is different: checked 2026-07-17, its testnet OID4VCI issuer advertises "format":"vc+sd-jwt" in its published metadata, the JOSE path, not JSON-LD. A stranger can check this directly:

curl -s https://capture-api.solidus.network/.well-known/openid-credential-issuer

This returns "format":"vc+sd-jwt", with no @context anywhere in the live wire format. So: the JSON-LD-framed credential shown in Solidus's docs is a documented design, not what a verifier receives from the live issuer today. This entry states that gap directly rather than letting the docs imply otherwise, full JSON-LD processing (context resolution, RDF canonicalization) is not part of Solidus's live path.