JSON Formatter & Validator
Paste any JSON to format it, minify it, or find exactly where a syntax error is located.
Formatted output will appear here.
What this formatter checks
JSON has strict syntax rules: keys must be double-quoted, trailing commas aren't allowed, and every bracket needs a matching pair. This tool parses your input with the browser's native JSON engine and reports the exact error message and, when available, the line and column where parsing failed.
Parsed entirely on your device
The JSON you paste is parsed and reformatted using your browser's built-in JavaScript engine. It is never transmitted to a server, which makes this tool safe for JSON containing sensitive configuration or API responses.
Frequently asked questions
Why does my JSON say "Unexpected token"?
This usually means there's a stray character, a missing comma, or a trailing comma before a closing bracket — check the reported line and column.
Can this handle very large JSON files?
Yes, though extremely large files (several megabytes) may take a moment to format depending on your device.
What does minify do?
Minify removes all unnecessary whitespace and line breaks, producing the smallest valid representation of the same data.
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