JSON Validator

Validate JSON syntax with detailed error reports

What is a JSON Validator?

A JSON Validator is a free online tool that checks JSON syntax and finds errors. It verifies that your JSON is well-formed and provides detailed feedback on any syntax errors. All validation happens in your browser.

How to Validate JSON

Paste JSON into the input field. The tool immediately checks the syntax and shows whether it's valid. If there are errors, it shows the exact location and cause.

Common JSON Errors

JSON syntax is strict. Common errors include missing commas, trailing commas, single quotes instead of double quotes, missing quotes, and unclosed brackets. The tool highlights the exact issue.

JSON Syntax Rules

  • Keys must be double-quoted strings
  • Strings must use double quotes
  • Trailing commas are not allowed
  • Comments are not allowed
  • Values must be strings, numbers, objects, arrays, true, false, or null

Frequently Asked Questions

How do I validate JSON?+
Paste JSON into the input field. The tool immediately checks the syntax and shows whether it's valid. If there are errors, it shows the exact location and cause.
What are common JSON errors?+
Common errors include missing commas, trailing commas, single quotes instead of double quotes, missing quotes, unclosed brackets, and invalid escape characters. The tool highlights the exact issue.
Can I validate large JSON files?+
Yes. Since validation happens in the browser, it can handle large JSON files. However, very large files (>50 MB) may be slow due to browser memory limits.
Does the validator fix JSON?+
No. The validator only checks the syntax and reports errors. You need to fix them manually. However, the error messages tell you exactly what and where to fix.
Is JSON data sent to a server?+
No. All validation happens locally in your browser. Your data never leaves your device.
Does the validator support JSON with comments (JSONC)?+
No. Standard JSON does not allow comments. If your JSON contains comments, you need to remove them before validating.

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JSON Validator — free online json validator, json syntax checker, json error finder, validate json online, check json, json parser, json debugger, json format validation. No signup required. Works in your browser.