JSON Formatter & Validator
Paste, type, or drop a file. Output updates as you type — nothing leaves your browser.
Try Repair JSON, , or .
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Same promise: fast, private, and nothing leaves your browser.
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Built to be the formatter you trust
A fast, clean JSON workspace without pop-up ads, sign-ups, or uploading your data anywhere.
- Private by design
- Everything runs locally in your browser. Safe for API keys, tokens and customer data.
- Precise errors
- Exact line and column with a plain-English explanation of what went wrong.
- One-click repair
- Fixes trailing commas, single quotes, comments, missing brackets and JSON pasted from AI chats.
- Big-number safe
- Keeps 64-bit IDs and number formatting exactly as written — no silent rounding.
- Tree explorer
- Browse huge documents and copy the JSONPath of any value with one click.
- Share without servers
- Links carry the data inside the URL fragment — never stored, never logged.
Frequently asked questions
Is my JSON uploaded to a server?+
No. Formatting, validation and repair all run in your browser. Share links store the data in the part of the URL after #, which browsers never send to servers.
Why does this formatter keep my large numbers intact?+
Most online formatters use JavaScript’s JSON.parse, which rounds integers above 9,007,199,254,740,991 — silently corrupting 64-bit IDs. This tool keeps every number exactly as written.
What can Repair fix?+
Trailing commas, single quotes, unquoted keys, comments, missing commas or brackets, Python-style True/False/None, and JSON wrapped in extra text such as an AI chat reply or a log line.
Is the AI free? Does it see my data?+
In desktop Chrome, Explain and AI Fix run on Chrome’s built-in on-device model — free, unlimited, and your JSON never leaves your computer. Large arrays are shortened before the model sees them.
How do I find a value deep inside a large document?+
Switch the output to Tree view, expand nodes, and click the path shown on hover to copy a JSONPath like $.users[3].email. Press Ctrl/Cmd+F inside either editor to search.