0-suite /
dev0

JSON Formatter & Validator

100% client-side. Your data never leaves this page. Verify: DevTools → Network.

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Output
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Paste JSON to validate and pretty-print it with 2-space, 4-space or tab indentation, or minify it to a single line. Invalid JSON shows the exact line and column of the first error. "Sort keys" recursively alphabetises object keys for stable diffs. All parsing runs locally in your browser — nothing is uploaded, so it's safe for production payloads.