Douglas Crockford originally specified the JSON format in the early 2000s; it was standardized in 2013 in RFC 7158 and ECMA-404. The latest RFC 8259 JSON format standard was published in 2017, and remains consistent with ECMA-404. The ECMA standard describes only the allowed syntax, whereas the RFC covers some security and interoperability considerations.
A restricted profile of JSON, known as I-JSON (short for “Internet JSON”), seeks to overcome some of the interoperability problems with JSON. It is defined in RFC 7493.