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JSON Formatter and Validator

Format, check and minify JSON, with errors shown by line.

Output
Style

Runs on your device. Nothing to upload.

What makes this formatter different

  • Numbers stay exact
  • Key order kept
  • Clear errors
  • Large files

Questions

How do I validate JSON?

Paste it in. If it’s valid you’ll see “Valid JSON” with a count of keys; if not, the error message gives the line and column of the first problem, such as a missing comma or a trailing comma before }.

Can it fix invalid JSON?

It points to the problem instead of guessing a fix, so nothing changes without you knowing. Common causes: single quotes instead of double quotes, comments, trailing commas, and unquoted keys.

What does “minify” do?

It removes all spaces and line breaks that aren’t needed, making the JSON as small as possible for sending or storing. The data itself doesn’t change.

Is my data sent anywhere?

No. Parsing and formatting happen in this browser tab. That matters when the JSON contains API keys, tokens or personal data.

Is it free? Do I need an account?

It is free to use and there is nothing to sign up for. There are no watermarks and no daily limits.

Missing something, or not working as it should? Tell us