Free tool · runs in your browser
JSON Formatter & Validator
Paste JSON to format, validate, minify or explore it. Errors point to the exact line and character.
Working with APIs?
Connect your tools and automate the busywork.
I build API integrations and AI automations that move data between your website, CRM, spreadsheets and apps, so nobody copies and pastes JSON by hand.
JSON syntax rules in brief
- Keys must be in double quotes:
{"name": "value"}. - Strings use double quotes only, never single quotes.
- No trailing commas after the last item in an object or array.
- No comments.
- Values can be strings, numbers,
true,false,null, objects or arrays.
Frequently asked questions
Is my JSON sent to a server?
No. Formatting and validation run in your browser, so it is safe for API responses, configuration files and data containing private details.
What are the most common JSON errors?
Trailing commas after the last item, single quotes instead of double quotes, keys without quotes, comments (JSON does not allow them), and missing commas between items. The error message shows the exact line and column.
What does "Try to fix" do?
It repairs the most common mistakes that come from copying JavaScript objects: it removes comments and trailing commas, swaps single quotes for double quotes, and adds quotes around keys. Always check the result.
What is the difference between formatting and minifying?
Formatting adds line breaks and indentation so people can read it. Minifying removes all unnecessary spaces so the file is as small as possible for sending over the network.
Is there a size limit?
Only your device's memory. Files of several megabytes format instantly; the tree view shows the first 2,000 items for speed.
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