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Free JSON Formatter & Validator Online
Free JSON Formatter & Validator Online is a free online tool by US AI. Pretty-print or minify JSON. It runs completely in your browser — no signup, no download, works on mobile and desktop.
📖 How to use
- Paste JSON and press Pretty Print to format it or Minify to compress it. Invalid JSON is flagged with an error.
- Open the tool with the button above — it loads instantly.
- Your work stays on your device; nothing is uploaded anywhere.
✨ Why use this tool?
US AI's free json formatter & validator online is fast, private and 100% free forever. Bookmark this page and share it with anyone who needs it.
❓ Frequently asked questions
How do I format JSON online?
Paste your raw JSON into the tool and press Pretty Print — it validates the structure and formats it with clean indentation instantly, all in your browser.
Does the JSON validator show what is wrong?
Yes. If your JSON is invalid, the tool flags the error so you can spot missing commas, quotes, or brackets and fix them fast.
Is my JSON data uploaded anywhere?
No. Formatting and validation run 100% locally in your browser — your data is never sent to a server or stored.