JSON Formatter and Validator
Pretty-print or minify JSON and find mistakes by line and column. Numbers and strings are kept exactly as you wrote them.
Nothing leaves your browser
How it works
- 1Paste JSONPaste it in or open a .json file up to 10 MB.
- 2Pick a layout2 or 4 spaces, tabs, or minified on one line. Sort keys if you want a stable order.
- 3Copy or downloadErrors point to the exact line and column, so you can fix them in place.
Questions
Is my text sent anywhere?
No. Everything runs in your browser and nothing you type or open is uploaded, logged or saved. Your settings are remembered on this device; your text isn't.
Will formatting change my numbers?
No. Many formatters run JSON through JSON.parse, which rounds big integers like IDs above 9007199254740991 and drops duplicate keys. This one keeps every value exactly as written and only changes the spacing.
Does it accept comments or trailing commas?
No, because standard JSON doesn't allow them and most parsers will reject them. The tool points to where they are so you can remove them.