JSON formatter
Validate, format and minify JSON while preserving number literals.
Content is processed in this browser, without upload or storage.
How it works & common questions
Is JSON uploaded?
No. Input stays in this browser and is not saved. Standard JSON is supported; comments, trailing commas and single quotes are syntax errors.
Are large integers and duplicate keys preserved?
Formatting and minification preserve original number and string literals, including large integers. Duplicate keys remain; downstream parsers may keep only the last value. Input is limited to 1 MB.