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What is JSON?

By Ada Lovelace· Published · Updated · Developer Tools

A plain-language reference for the JSON data interchange format, its grammar, and its limits.

JSON is a text format for structured data built from objects, arrays, strings, numbers, booleans, and null. RFC 8259 defines the grammar; it does not define a schema.

What JSON is not

JSON is not a schema language and not a substitute for application validation. Two documents can both be valid JSON and still disagree about fields and types.

Frequently asked questions

Is JSON the same as JavaScript objects?
No. JSON is a stricter text grammar; it disallows trailing commas, comments, and unquoted keys that JavaScript object literals may allow.

Sources

  1. RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format — IETF (accessed 2026-09-01)

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