The Wolfram Language has built-in support for a variety of types of JSON, as well as a variety of standard mappings between JSON data structures and Wolfram Language structures.

"RawJSON" — nested lists and associations mapped to JSON (.json)

"JSON" — lists and lists of rules mapped to JSON (.json)

"ExpressionJSON" — full Wolfram Language expressions mapped to JSON (.json)

Binary JSON Formats

"UBJSON" — nested lists and associations mapped to UBJSON (.ubj)

JSON Data Storage Formats

"BSON" — binary format used by MongoDB, etc. (.bson)

"JSONLD" — JSON format for linked RDF data (.jsonld)

"SPARQLResultsJSON" — format used by SPARQL endpoints (.srj)

Domain-Specific JSON Formats

"GeoJSON" — geo data mapped to JSON (.geojson)