Developer

JSON Formatter

Paste any JSON to pretty-print it, minify it, or check whether it's valid — with a clear error message when it isn't.

Paste JSON

Indent size

Result

How to use the json formatter

Paste your JSON into the box.
Click Format to pretty-print it, Minify to compress it to one line, or Validate to just check it.
If the JSON is invalid, the error message explains what the parser objected to.

Features

Format with 2-space, 4-space or tab indentation
One-click minify for production use
Validate-only mode with a specific error message
Copy or download the result as a .json file

Format JSON for debugging

Pretty-printed JSON is easier to inspect because objects, arrays and nested values are indented consistently. Minified JSON removes that extra whitespace when you need a compact payload.

Validation errors usually come from missing commas, unmatched brackets, unquoted property names or invalid escape characters. Fix the first reported structural error and validate again, because one early mistake can cause several later-looking errors.

Do not paste secrets, private keys or production credentials into tools you do not trust. ToolNova formats the text in your browser, but good security practice is still to use sample or redacted data when debugging shareable examples.

Frequently asked questions

Common causes are trailing commas, single quotes instead of double quotes, or an unquoted key — standard JSON requires double-quoted keys and no trailing commas.

No, parsing and formatting happen locally in your browser using the standard JSON.parse function.

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Formatting helps you inspect structure, not validity alone

Pretty printing makes nested data easier to read, while validation tells you whether the text follows JSON syntax. A valid JSON document can still contain the wrong fields or values for the API that consumes it.

Fix syntax errors before debugging application logic.
Check data types such as strings, numbers and booleans against the API contract.
Avoid pasting secrets or production tokens into tools you do not trust; this formatter runs in your browser.