Format and check your JSON
Paste JSON to see it neatly indented, or find the exact line and column of what's wrong. Common mistakes — comments, trailing commas, single quotes — can be repaired in one click. Big numbers and key order are never changed.
Runs in your browser — nothing is uploaded
How to use it
- 1Paste your JSON into the top box, or drop a .json file on it.
- 2If something is wrong you see the line and column. If it can be repaired, the fixes are listed and the result is shown.
- 3Choose 2 spaces, 4 spaces, tab or minified, then copy or download the result.
Related tools
Frequently asked questions
How do I find the error in my JSON?
The tool shows the line and column of the first problem, the line itself with an arrow under it, and a plain-language reason — for example a missing comma, a stray comma before a closing bracket or a string without a closing quote. “Show me where” puts the cursor there.
Can it fix broken JSON automatically?
It repairs the common mistakes: comments, trailing commas, single-quoted strings, keys without quotes, and Python-style True, False and None. Every fix is listed so you can check it. Anything else (for example a missing bracket) is reported as an error rather than guessed.
Will it change my numbers or the order of my keys?
No. Numbers are kept exactly as you typed them, even ones with more digits than JavaScript can hold, and keys stay in the order you wrote them unless you tick “Sort keys A → Z”.
What is the difference between formatting and minifying?
Formatting adds line breaks and indentation so people can read it. Minifying removes all the extra spaces so the file is as small as possible. The data is identical either way.
Is my JSON uploaded?
No. It is checked and formatted in your browser and never leaves your device, so it is safe to use with private data. Files up to 5 MB are supported.