JSON Validator

Paste JSON and click Validate to find syntax errors with their exact line and column, then format or minify it.

Updated 100% free Files stay on your device No sign-up

Watch the 0:36 video tutorial
JSON Validator illustration
Input JSON
Output

How to use the JSON Validator (video)

0:36 · no sound needed
In this video
  1. Paste your JSON
  2. Click Validate – the error and its position are shown
  3. Fix the mistake (here: a trailing comma)
  4. Validate again – then Beautify

How to validate JSON

  1. Paste your JSON into the input box above.
  2. Click Validate. Valid JSON shows a green tick; invalid JSON shows the error with its line and column.
  3. Fix the error, validate again, then click Beautify or Minify.

The most common JSON errors

  • Trailing comma: {"a": 1,}. Remove the comma after the last item.
  • Single quotes: {'a': 'b'}. JSON requires double quotes.
  • Unquoted keys: {a: 1} must be {"a": 1}.
  • Comments: // and /* */ are not allowed in standard JSON.
  • Missing brackets: every { and [ needs a closing partner.
  • Invalid values: undefined, NaN and functions are not valid. Use null.

Who uses a JSON validator?

Developers testing API responses, marketers editing tracking configs and schema markup, and anyone working with settings files for apps, plugins or automation tools. Invalid JSON often breaks a whole feature silently, so checking it first saves time.

Private by design

Validation runs in your browser, so API keys, tokens and customer data in your JSON never leave your device. Need to encode data? Try the Base64 encoder or URL encoder.

Frequently asked questions

How do I know if my JSON is valid?

Paste it and click Validate. You will see either a success message or the first error with its line and column.

Can JSON contain comments?

Standard JSON does not allow comments. Some tools accept JSONC or JSON5, but most APIs do not.

Is my JSON uploaded?

No. Validation happens in your browser.