JSON Formatter Calculator
Beautify JSON with 2- or 4-space indentation, or minify it to a single line — with a validity check and a structure summary.
How it works
beautify = JSON.stringify(value, null, indent) · minify = JSON.stringify(value) · both first validate by JSON.parse
JSON has one grammar but two everyday shapes: an indented, line-broken form that people read, and a whitespace-free form that machines send. This tool parses the input first — which is the real validity check, since a single missing comma or unquoted key makes it unparseable — then re-serializes it. Beautifying adds newlines and 2 or 4 spaces of indentation per level; minifying removes every optional space and newline. Because it round-trips through a parser, the output is always canonical JSON: keys keep their order, but trailing commas, comments and single quotes (none of which are legal JSON) are rejected with the parser’s own error message.
Worked example
The compact object {"name":"InfyCalc","tags":["fast","free"],"count":42,"nested":{"ok":true}} is valid JSON: a top-level object with 4 keys, 74 characters when minified. Beautified with 2 spaces it becomes a multi-line, indented block with "tags" and "nested" opened out one level in; minifying it again returns the original single line.
Sources: JSON.stringify() — MDN
Frequently asked questions
Does formatting change my data?
No — only the whitespace between tokens changes. Object keys, array order, numbers and strings are all preserved exactly. Beautify and minify are perfectly reversible; they never add, drop or reorder any value.
Why does it reject JSON that "looks fine"?
Strict JSON forbids trailing commas, comments, single-quoted strings and unquoted keys — all common in JavaScript object literals but not in JSON. The parser reports the exact position it choked on, which is usually where one of those crept in.
Should I send minified or beautified JSON?
Minify for anything that travels — APIs, storage, config sent over the network — because it is smaller and parses identically. Beautify only for reading and debugging. Compression (gzip) narrows the size gap, but minified still wins on payload and parse time.
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This calculator is for educational purposes. Double-check important results before acting on them.