Valid
✓ Valid JSON.
JSON Validator
Validate JSON syntax instantly in your browser and get a clear pass/fail result with the exact error. Free online JSON validator — no data uploaded.
Enter the values below, then press Calculate (or press Enter). The calculator updates your results instantly. Try different values to see how your inputs change the outcome.
- JSON to validate — enter a value. A typical JSON to validate would be Paste JSON to check here….
- Review your results — the key output is highlighted, with supporting figures below.
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Results
Result
| Detail | Value |
|---|---|
| Details |
What is this calculator for?
Check whether a block of text is syntactically valid JSON, with a clear error when it is not.
How to Use This Calculator
Enter the values below, then press Calculate (or press Enter). The calculator updates your results instantly. Try different values to see how your inputs change the outcome.
- JSON to validate — enter a value. A typical JSON to validate would be Paste JSON to check here….
- Review your results — the key output is highlighted, with supporting figures below.
What You'll Need
- JSON to validate
- a value · required
About This Calculator
This JSON validator parses your input with the same rules a browser or JavaScript runtime uses for JSON.parse, then reports a clear pass or fail.
JSON must use double quotes, must not contain trailing commas or comments, and every opening brace/bracket must be closed. When the input is invalid, the tool surfaces the parser’s exact error (such as position of a missing comma or brace) so you can fix it quickly.
Validation runs locally — nothing is uploaded, so it is safe for configuration snippets and payloads.
Worked Examples
Invalid
✗ Invalid JSON.
Frequently Asked Questions
Are single quotes allowed in JSON?
No. JSON requires double quotes for all strings. Many editors accept single quotes, but strict JSON (and JSON.parse) does not.
Can this validator check for duplicate keys?
It checks syntax validity only. Duplicate keys parse successfully (the last one wins) but this tool still marks the JSON as valid.