JSONlike

JSONlike is a term used to describe data formats or syntaxes that resemble JSON but are not identical to the official JSON specification. It denotes formats that adopt JSON-like structures—objects as key-value maps, arrays, strings, numbers, booleans, and a null value—while relaxing or altering some JSON rules. Typical deviations include allowing comments in data, trailing commas after lists or objects, single-quoted strings, or unquoted keys in some variants.

Core characteristics of JSONlike formats include human readability and broad tooling support, combined with a more permissive grammar. However, the relaxed rules can reduce interoperability with strict JSON parsers and may introduce ambiguities if different parties use different variants.

Variants and examples often cited as JSONlike include JSON5, HJSON, and other relaxed or human-friendly supersets of JSON. JSON5 formalizes features such as single-quoted strings, trailing commas, and more permissive syntax, while HJSON emphasizes readability with optional punctuation and comments. Some programming languages offer emulated JSON-like object literals that resemble JSON but diverge in grammar or allowed constructs.

Usage considerations center on trade-offs between ease of editing and interoperability. For configuration files and local development workflows, JSONlike formats can improve manual editing and clarity. For data interchange between diverse systems, strict JSON is generally safer. When using JSONlike formats, it is important to ensure all participants and tools agree on the variant and to consider conversion to strict JSON for compatibility when needed.

Relation to standard JSON: JSON itself is defined in RFC 8259 (and ECMA-404). JSONlike formats extend JSON’s data types while differing in syntax, intended for human-friendly editing or specific tooling scenarios rather than universal standardization.