Toolwyn

JSON formatter

BETA

Format, minify, and validate JSON. Runs entirely in your browser.

Input
Output

Your JSON never leaves your device. Nothing is uploaded to a server.

Report a problem

Frequently asked questions

Will this tell me exactly what's wrong with invalid JSON?

Yes — invalid JSON shows a specific parser error message (like which character or line caused the problem) instead of just "invalid."

Is there a size limit on the JSON I can format?

No hard limit, but extremely large JSON (tens of MB) may be slow to format since it all happens in your browser's memory.

What's the difference between Format and Minify?

Format adds indentation and line breaks for readability; Minify strips all unnecessary whitespace to make the JSON as small as possible for production use.

Does this validate against a JSON Schema?

No, it only checks that the JSON is syntactically valid (correctly structured), not that it matches a particular schema or shape.