JSON⇄XML
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Free JSON Validator

Check JSON syntax instantly with error line and column numbers. Runs in your browser — your data never leaves your machine.

JSON Input
Validation Result

Paste or upload JSON to validate…

🔒 100% Private

All validation happens in your browser using JavaScript. Nothing is uploaded to any server. Safe for sensitive business data.

⚡ Real-time

Validation runs as you type — no button to click. See results instantly as you paste or edit your JSON.

📍 Error Location

When your JSON is invalid, see the exact line and column number where the error was detected, along with a descriptive error message.

How to Validate JSON Online

Paste your JSON into the left panel and the validation result appears instantly on the right. A green checkmark means your JSON is valid. A red error shows the exact problem with line and column numbers. You can also drag and drop a .json file or use the upload button.

Common JSON Syntax Errors

The most frequent JSON errors developers encounter are: trailing commas after the last element in an array or object, using single quotes instead of double quotes, forgetting to quote object keys, including comments (not allowed in JSON), and unescaped special characters like backslashes or newlines in strings.

Frequently Asked Questions

What does a JSON validator do?
A JSON validator checks whether your JSON is syntactically correct according to the JSON specification (RFC 8259). It catches missing commas, unclosed brackets, trailing commas, single quotes, and other common mistakes.
Is this JSON validator free?
Yes — completely free, forever. No sign-up, no account, no usage limits.
Is my data safe?
All validation happens locally in your browser using JavaScript. Your JSON is never uploaded to any server. It's safe to use with sensitive or proprietary data.
Does it show where the error is?
Yes — when your JSON is invalid, the validator shows the error message along with the line and column number where the problem was detected, so you can find and fix it quickly.
What are common JSON errors?
The most common JSON errors are: trailing commas after the last item, single quotes instead of double quotes, missing quotes around keys, unescaped special characters in strings, and comments (JSON doesn't support comments).
What's the difference between a validator and a linter?
A validator checks whether JSON is syntactically valid. A linter goes further and checks for style issues like inconsistent formatting. This tool is a validator — for formatting, use the JSON Formatter.
Can I also format my JSON?
Yes — use the JSON Formatter to pretty-print or minify your JSON with configurable indentation.

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