JSONTech

JSON Validator

Validate JSON with detailed error messages and line numbers

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Frequently Asked Questions

Paste your JSON into the editor and click Validate. The tool checks your JSON against the official RFC 8259 specification and shows exact line numbers and descriptions for any errors found.

The top five JSON errors developers encounter are: trailing commas after the last item, single quotes instead of double quotes, unquoted property names, missing commas between items, and comments (JSON doesn't support comments).

No. Standard JSON (RFC 8259) does not support comments of any kind — not //, not /* */, not #. If you need comments, consider JSONC or JSON5 formats, or use our JSON Repair tool to strip comments automatically.

Invisible characters are a common culprit. Check for non-breaking spaces, zero-width characters, or BOM markers. Also watch for smart quotes (curly quotes) that text editors sometimes auto-insert.