Use of NIEM JSON does not require any use of XML; NIEM JSON exchanges are pure JSON, with JSON-LD providing some features of XML and JSON Schema providing some features of XML Schema. For users already familiar with XML, the NTAC produced Non-Normative Guidance in Using NIEM with JSON. This document lays out how a NIEM IEPD describes a JSON message, by showing that XML elements, attributes, and other features can be expressed as JSON objects. These guidelines highlight the use of JSON-LD for namespace-qualified names, the RDF conceptual model used by NIEM, and linked data methodologies.
The NIEM data model contains many community-agreed data definitions suitable for reuse. The names of JSON object properties can reuse the terms and namespaces of NIEM data definitions, allowing for reuse of data definitions across XML and JSON, and supporting JSON exchanges for data previously defined for XML.
NIEM has published a JSON-LD context for the NIEM 4.0 release, which provides a Uniform Resource Identifier (URI) mapping for each conformant namespace used in NIEM. This provides JSON users an easy way for JSON messages to use and reference the model, providing an easy-to-use linked data approach to NIEM.