How to use the JSON Formatter & Validator
- Paste JSON (or open a .json file).
- Click “Format” to beautify or “Minify” to compress.
- If there’s an error, fix it at the line and column shown, then copy or download the result.
About this tool
JSON is strict: keys must be in double quotes, strings can’t use single quotes, and a comma after the last item in an object or array (a “trailing comma”) is an error. When parsing fails, the validator shows the line and column where the problem was detected and the text around it — the actual mistake is usually there or just before it.
Formatting re-indents the data so it’s easy to read; minifying removes all spaces and line breaks to make API payloads and config files smaller. Your JSON never leaves your browser, so it’s safe to paste API responses that contain tokens or customer data.
Frequently asked questions
Why is my JSON invalid?
The most common causes are trailing commas, single quotes instead of double quotes, unquoted keys, and comments — none of which are allowed in standard JSON.
Does the formatter change my data?
No. Values are kept exactly; only whitespace changes. “Sort keys” reorders object keys alphabetically if you tick it.
Is it safe to paste sensitive JSON?
Yes. Parsing and formatting happen in your browser and nothing is uploaded.
How large a file can it handle?
Several megabytes is fine on most devices. Very large files depend on your device’s memory.