JSON formatter & validator
Format JSON so it is easier to read, check for errors, or minify it into compact text. Numbers and the order of your data stay unchanged.
Paste your JSON, then choose Format JSON.
Add your text to get started.
Your original text stays unchanged unless you replace it.
Formatting without rewriting your data.
Format JSON adds spacing and line breaks for easier reading. Make compact removes that extra spacing (minifies the JSON). Both keep your values, including every digit in large numbers.
What counts as valid JSON?
JSON allows objects, arrays, strings, numbers, true, false, and null. Property names need double quotes. Comments, trailing commas, single-quoted strings, undefined, and NaN are not JSON.
What does Check JSON check?
It checks the rules for writing JSON, not whether the data is right for your app. Missing fields and duplicate keys can still cause problems. Formatting preserves duplicate keys and the original key order.
How do I fix an error?
The error message points to the problem when possible. Check that spot and the character before it for a missing quote, comma, or bracket. Your text is kept so you can fix it.
File limits & shortcuts
Use up to 1,000,000 characters at a time. You can also open a text file up to 4 MB, saved as UTF-8. These limits help keep your browser responsive.
Press Ctrl + Enter (⌘ + Enter on Mac) to run the first action.