What is JSON?
JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is derived from JavaScript object literal syntax but is language-independent and supported natively by virtually every programming language and platform.
JSON represents data as a combination of six value types: strings (double-quoted Unicode text), numbers (integer or floating-point), booleans (true or false), null, arrays (ordered lists of values), and objects (unordered key-value maps). These primitives compose recursively, allowing JSON to represent any hierarchical data structure.
The format was formalised in RFC 8259 and ECMA-404. Key rules: object keys must be strings, strings must be double-quoted (single quotes are invalid), trailing commas are not allowed, and comments are not part of the standard (JSON5 and JSONC are extensions that relax these constraints).
JSON replaced XML as the dominant web API format starting around 2005 because it is less verbose, easier to parse, and maps naturally to data structures in most programming languages. REST APIs return JSON, configuration files (package.json, tsconfig.json, .prettierrc) use JSON, and databases like PostgreSQL and MongoDB have native JSON column types.
Pretty-printing (adding indentation and newlines) makes JSON human-readable during development; minifying (removing whitespace) reduces payload size for production use.
quickhelp.dev's JSON Formatter pretty-prints, minifies, and validates JSON in the browser. The JSON to CSV tool converts flat JSON arrays to tabular format for use in spreadsheets and data tools.