JSON formatter
Format, validate and minify JSON, with the exact line and column of any error.
Runs in your browser. Your input is processed on this device. It is never uploaded or stored.
Paste JSON or open a file to begin.
How it works
Input is checked against the JSON standard (RFC 8259) as you type, and formatted or minified in a background thread. The JSON is only read as data; it is never run as code.
- Values are preserved exactly. Numbers keep every digit as written (no rounding of large integers or long decimals), strings keep their escape sequences, and object keys stay in their original order. Only whitespace changes.
- Errors show the line and column of the first problem, counted in characters, with an explanation of common mistakes: trailing commas, single or curly quotes, comments, unquoted property names, and invisible characters copied from web pages.
- Warnings point out valid JSON that other programs may misread: duplicate property names, and numbers that 64-bit floating point cannot represent exactly.
- Limits: up to 5,000,000 characters of input and 1,000 levels of nesting.
Your JSON stays on this device. It is not uploaded, logged or saved.
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