Formatereur JSON
Formater, validate, and minify JSON with instant syntax detection. Gratuit, in-browser, private.
What is JSON formatting?
JSON (JavaScript Object Notation) is the data format used by virtually every modern API, database, and configuration file. It is compact, but raw JSON is usually written as one long, unbroken line, which makes it nearly impossible to read, audit, or debug. Formaterting — also called beautifying or pretty-printing — adds indentation and line breaks so the structure of objects, arrays, and values becomes visible at a glance.
This free JSON formatter does more than beautify. It validates your input and pinpoints syntax errors, such as missing commas, unquoted keys, or trailing commas, before they break your code. It can also minify formatted JSON back into a single line for storage or transfer. Everything runs locally in your browser: paste, format, validate, copy. No upload, no signup, no limits.
Comment faire use the JSON formatter
- Paste your JSON into the box — both minified and already-formatted input are accepted.
- Click Formater to beautify with 2-space indentation, Minify to compress to one line, or Valider to check for syntax errors.
- Copier the result with one click — invalid JSON shows the exact parser error so you can fix it fast.
Frequently asked questions
What is a JSON formatter?
A JSON formatter, or beautifier, takes raw JSON and adds indentation and line breaks so the data structure is easy to read and debug. This tool also validates and minifies your JSON.
Is this JSON formatter free?
Yes — completely free, with no limits, no signup, and no watermark. Use it as often as you like, even for large files.
Is my JSON sent to a server?
No — everything is parsed and formatted locally in your browser. Your data never leaves your device and nothing is stored or tracked.
How do I fix invalid JSON errors?
The Valider button reports the exact error message from the JSON parser, so missing commas, unquoted keys, and trailing commas are easy to locate and correct.