Can I format JSON without uploading my data?
Yes. Formatting and validation run inside your browser. Pasted text and local files are kept in page memory and are not sent to a conversion server. Refreshing or navigating away clears them.
Format & validateTHE SMALL TOOLS THAT MAKE A BIG DIFFERENCE
JSON Formatter.
Format, validate, and minify JSON in your browser. Choose your indentation, then copy or download the result. No uploads or sign-up.
100% browser-based
Input
JSONOutput
JSONA clearer view, coming right up.
Your formatted JSON will appear here.
Hit “Format JSON” to get startedOnly your browser sees your data. 2 MB input limit.No uploads. No sign-up. Just tools.
A QUICK WALKTHROUGH
Good data, in three steps.
Simple by design. Ready when you are.
- 01
Bring your data
Paste your JSON, choose a local file, or try our example.
- 02
Make it yours
Choose an indentation size and select Format JSON. Use Minify for compact output or Validate to check syntax.
- 03
Keep things moving
Copy the result or download it as a .json file.
A few things under the hood
Know exactly how your data is handled.
JSON formatting & validation rules
- Accepts any JSON value: objects, arrays, strings, numbers, booleans, and null. A leading UTF-8 byte-order mark is ignored.
- Strict JSON only: double-quoted keys and strings, with no comments or trailing commas.
- Uses native JavaScript JSON semantics. Duplicate keys keep the last value; numbers beyond JavaScript precision may lose digits and numbers outside the finite numeric range are rejected. Keep large identifiers as strings.
- All tools accept UTF-8 text up to 2 MB and nesting up to 80 levels. Results are limited to 8 MB. CSV tables are limited to 1,000,000 cells including headers; XML is additionally limited to 50,000 elements. Results are held only in this page’s memory; refreshing or navigating away clears them.
COMMON QUESTIONS
JSON Formatter questions
Answers for working with real data.
Why is my JSON invalid?
JSON requires double quotes around property names and strings. Comments, trailing commas, missing commas, and unmatched brackets are rejected. Validate checks JSON syntax; it does not validate a JSON Schema.
Will formatting preserve large numbers exactly?
JavaScript number precision applies. Integers beyond Number.MAX_SAFE_INTEGER may lose digits, so keep large identifiers as quoted strings. Duplicate object keys keep their last value.