JSON Formatter & Validator
Format, validate, and minify JSON. Highlights syntax errors.
JSON Formatter helps you format (beautify), validate, and minify JSON data online. It's handy for debugging API responses, reading long, hard-to-parse config files, or cleaning up data before using it in code. Sensitive data like tokens or API keys stay safe here since all processing happens right on your machine.
How to use JSON Format / Validate
- Paste your JSON string into the input box.
- Click "Format" for clean, readable indentation, or "Minify" to compress it to a single line.
- If the JSON has a syntax error, the tool will flag it and point to the exact location so you can fix it.
- Copy the result to use elsewhere.
What's the difference between Format and Minify?
Format (beautify) adds indentation and line breaks so humans can read the content and spot errors easily — useful when debugging or reviewing. Minify strips all unnecessary whitespace to shrink the JSON down to its smallest size — useful when sending it over a network, storing it in a constant, or embedding it compactly in a config.
Common JSON errors
Most errors come from a trailing comma at the end of a list or object, using single quotes instead of double quotes for keys and strings, a missing closing bracket, or a // comment (standard JSON doesn't allow comments). When validation flags an error, check the exact location it points to for a quick fix.
Frequently asked questions
Is my JSON data sent anywhere?
No. All processing runs right in your browser, so no data is ever sent to any server.
Can it handle large JSON files?
Yes, the tool can handle JSON files with thousands of lines since it runs directly in JavaScript on your machine.
What's the point of minifying JSON?
Minifying removes unnecessary whitespace, reducing the size for network transfer or storage without changing the data's content.
Does JSON allow comments?
Standard JSON doesn't support comments. If your file has // or /* */, that's JSON5/JSONC — you'll need to strip the comments before validating it with this tool.