JSON Formatter and Validator
Pretty-print, minify and validate JSON with clear error positions.
How to use this tool
- 1Paste your JSON into the input area.
- 2Click Format to indent it, or Minify to strip whitespace.
- 3Read any error message, which points to the exact position of the problem.
- 4Copy the cleaned-up JSON.
About this tool
JSON is easy to read when it is formatted and almost impossible when it arrives as a single 40,000-character line from an API response or a log file. Formatting adds indentation and line breaks so structure becomes visible, which is usually all you need to spot that an array is nested one level deeper than you assumed. Validation catches the small syntax mistakes that break parsers: a trailing comma after the last element, single quotes instead of double, an unescaped quote inside a string, or a missing closing brace. The error message points at the position so you are not hunting blind. Minifying does the reverse, stripping every unnecessary byte for config files and payloads where size matters. Everything runs locally, so API keys and customer data in your payload never leave the browser.
Frequently Asked Questions
Is my JSON sent to a server?
+
No. Parsing and formatting happen entirely in your browser, which matters when payloads contain tokens or personal data.
Why is my JSON invalid when it looks fine?
+
The usual culprits are trailing commas, single quotes, comments, or unescaped characters inside strings. Strict JSON allows none of them.
Can it handle large files?
+
Yes, within your browser's memory. Documents of a few megabytes format without trouble on most machines.