What is the JSON Formatter & Validator?
JSON Formatter & Validator by Assignment Lab is a free online tool. Paste JSON to format it neatly, minify it, sort keys, and find the exact line of any error. Free, instant and private.
At a glance
- Price
- Free. No sign-up, no watermark.
- Works on
- Phone, tablet and computer, in any modern browser.
- Privacy
- Runs in your browser. Your text and files are not uploaded.
- Made by
- Assignment Lab, free tools for students in India.
How to use the json formatter
- Paste your JSON into the box.
- Press Format to make it readable, or Minify to squeeze it onto one line. Tick "sort keys" to order keys A–Z.
- If the JSON is broken, the note shows the line and column, and the cursor jumps to the problem.
Frequently asked questions
Is my JSON sent anywhere?
No. Formatting and checking happen in your browser, so private data like API responses stays on your device.
What are the most common JSON mistakes?
A comma after the last item, single quotes instead of double quotes, and keys without quotes. JSON needs "double quotes" around every key and text value.
Is it free?
Yes. The JSON Formatter & Validator on Assignment Lab is completely free with no sign-up, and it works right in your browser. Nothing you type or add is uploaded.
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