Paste or type JSON — get formatted output instantly, or minify it. Error messages show line + column. Everything runs locally.
Runs entirely in your browser. Your data never leaves your device.
"name" not name or 'name')string, number, true, false, null, object, array| Input | Format | Minify |
|---|---|---|
{"a":1,"b":[2,3]} | 2-space indented | {"a":1,"b":[2,3]} |
Invalid: {"a":1,} | Error: trailing comma | |
Invalid: {name:"x"} | Error: unquoted key | |
Uses browser's native JSON.parse for strict validation. Last checked: September 2026.
No. The entire formatter, validator, and minifier runs locally in your browser using vanilla JavaScript. Your JSON is never uploaded or transmitted.
We use the browser's native JSON parser, which catches everything: missing commas, trailing commas, unquoted keys, mismatched braces/brackets, unterminated strings, and invalid escape sequences. We also show the exact line and column of the error.
We use 2-space indentation (the most common style in modern APIs and config files). Minification strips all whitespace while preserving the exact data structure.
Your text is parsed with the browser’s native JSON parser and rebuilt, so valid JSON comes back functionally equivalent. Two edge cases worth knowing: duplicate keys collapse to the last value, and extremely large or high-precision numbers follow JavaScript number rules, which can round them.
This tool only accepts text that already is JSON. For tabular data, start with our CSV to JSON Converter, which turns CSV text into JSON right in your browser — then paste the result here to pretty-print or minify it.
Formatting is just step one: export your data as YAML with JSON to YAML, compare two payloads key by key with JSON Diff, or inspect tabular exports in the CSV Viewer before converting them.
If you just finished with JSON Formatter & Validator, the natural next steps are UUID Generator, Regular Expression Tester, Number Base Converter, or browse every tool in Daily Tools.