Free Online JSON Formatter & Validator
Format, validate, and minify JSON data instantly in your browser. Paste or type JSON to pretty-print it with 2-space indentation, or minify it for production. Only whitespace changes, so large integer IDs, number formatting, key order and duplicate keys stay exactly as written. Reports parse errors, with the line and column whenever the browser gives a position. 100% private — nothing is uploaded or stored.
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Frequently Asked Questions
Yes — all processing happens in your browser. Nothing is sent to any server.
It shows the parser's error message, plus the line and column when the browser reports a position, so you can fix it quickly, but it doesn't auto-correct.
Format adds indentation and line breaks for readability. Minify removes all whitespace to reduce size for production use. Both only change whitespace: numbers (including IDs larger than 2^53), escapes, key order and duplicate keys are copied unchanged.
No hard limit — it depends on your browser's available memory. Works well with files up to several MB.