Why an Ecma Standard?
By 2013, JSON had already been the dominant data interchange format for web APIs for several years. The only formal specification was Douglas Crockford's RFC 4627, published in 2006 by the IETF. While RFC 4627 was authoritative in internet protocol contexts, the Ecma standardisation route offered a different kind of legitimacy: ISO/IEC fast-track publication, formal adoption by national standards bodies, and recognition in government procurement contexts that require international standards.
Crockford participated in the process alongside the Ecma TC39 committee (which also maintains ECMAScript, the JavaScript specification). Publishing ECMA-404 gave JSON the same level of formal recognition as HTML (W3C) and ECMAScript (Ecma) — an important signal for enterprise adoption.
A Deliberately Minimal Specification
ECMA-404 First Edition is about six pages of normative content. This brevity was a conscious choice. The document defines:
- The six JSON value types: object, array, string, number, boolean (true/false), and null
- The grammar for each type using a simple BNF-like notation
- String escaping rules for control characters and non-ASCII characters
- Number syntax (integer, fractional, exponent parts)
What it deliberately does not define: semantics of values, behaviour when parsing malformed input, encoding (leaving that to the IETF RFC), number precision, or duplicate key handling. The minimalism makes ECMA-404 a stable, timeless grammar reference rather than a comprehensive implementation specification.
The RFC and Ecma Tracks
When ECMA-404 was published in October 2013, the active IETF JSON standard was RFC 4627 (2006). RFC 7159 was published five months later in March 2014. This created a brief period of three active authoritative documents, each with slightly different wording.
The IETF and Ecma tracks have run in parallel since 2013. Their content is now synchronised (following the simultaneous publication of RFC 8259 and ECMA-404 Second Edition in December 2017), but they serve different audiences and citation contexts. ECMA-404 is referenced in language specifications; RFC 8259 is referenced in protocol standards and API specifications.
Impact on Adoption
ECMA-404's publication accelerated JSON adoption in regulated industries and government systems where procurement rules require ISO or IEC standards. As an Ecma standard, ECMA-404 can be submitted for fast-track publication as an ISO/IEC standard, giving JSON the same formal pedigree as standards like SQL (ISO/IEC 9075) or C (ISO/IEC 9899).
The combination of the IETF RFC track (RFC 8259) and the Ecma/ISO track (ECMA-404) means JSON is one of the few data formats with formal recognition from both bodies — a significant factor in its near-universal adoption across industries.