Developer Tools
JSON Formatter
Pretty-print, minify, and validate JSON locally in your browser.
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About this tool
Paste JSON to format with adjustable indent, minify it back to a single line, or validate with precise line/column error reporting. Round-trips losslessly and handles BigInt-ish numbers without precision loss in most cases.
Frequently asked questions
Will my data be uploaded?
No. Formatting happens entirely in your browser. The JSON never leaves your device.
Why does my big integer lose precision?
JavaScript numbers are 64-bit floats. Integers above 2^53 lose precision through `JSON.parse`. For full fidelity on huge integers, use a JSON parser with BigInt support.