Pasting a minified API response and getting back something a human can scan. Catching syntax errors — trailing commas, unquoted keys, smart quotes — with the exact line/column the parser tripped on. Stripping whitespace before pasting JSON into a context where size matters (URL params, env vars, config files). Confirming your hand-written JSON is valid before piping it into another tool.

JSON ≠ JavaScript object literal. Keys must be in double quotes. Single quotes, unquoted keys, and trailing commas all fail. If you've got JS object literals, run them through a converter first. Smart quotes from copy-paste. Word processors and chat apps love to "helpfully" replace " with " / " . Those aren't valid JSON delimiters. JSON has no comments. If your "JSON" has // or /* */ , it's actually JSONC (used by VS Code config) — strip those before parsing. Numbers larger than 2⁵³. JavaScript can't represent integers above 9007199254740992 exactly. Twitter snowflake IDs and similar should be quoted as strings.

Formateador JSON

Formatea, valida y minifica JSON al instante. Los errores se resaltan con línea y columna.

Entrada

Salida

Introduce un valor arriba para ver el resultado.

What is this for?

JSON travels minified — every byte counts when an API response is being shipped. But minified JSON is unreadable. This tool round-trips through the browser's native JSON.parse / JSON.stringify to produce indented, copy-able output, validate the structure, or strip whitespace back out. Nothing is uploaded; everything happens in the page.

When to use it

Pasting a minified API response and getting back something a human can scan.
Catching syntax errors — trailing commas, unquoted keys, smart quotes — with the exact line/column the parser tripped on.
Stripping whitespace before pasting JSON into a context where size matters (URL params, env vars, config files).
Confirming your hand-written JSON is valid before piping it into another tool.

Common gotchas

JSON ≠ JavaScript object literal. Keys must be in double quotes. Single quotes, unquoted keys, and trailing commas all fail. If you've got JS object literals, run them through a converter first.
Smart quotes from copy-paste. Word processors and chat apps love to "helpfully" replace " with " / ". Those aren't valid JSON delimiters.
JSON has no comments. If your "JSON" has // or /* */, it's actually JSONC (used by VS Code config) — strip those before parsing.
Numbers larger than 2⁵³. JavaScript can't represent integers above 9007199254740992 exactly. Twitter snowflake IDs and similar should be quoted as strings.