How to Format and Validate JSON (Free Online Tool)

APIs return JSON as one unreadable line, and a single misplaced comma breaks parsing. Formatting and validating it is the fastest way to debug.

Format and validate

Paste minified JSON into the JSON formatter for clean, indented output — or the exact error if it's invalid. The JSON validator pinpoints syntax problems by position. Both run in your browser, so API responses with tokens stay private.

The errors to check first

Trailing commas (legal in JS, fatal in JSON), single quotes (JSON needs double), unquoted keys, comments (JSON has none), and truncated data. If the error is at position 0 with a "<" token, you're parsing an HTML error page, not JSON.

Minify for production

Once your JSON works, the JSON minifier strips whitespace to shrink payload size for production APIs and config.

Convert formats

Need a spreadsheet? The JSON to CSV converter turns an array of objects into CSV. Going the other way, CSV to JSON handles imports.

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