JSON Validator Online
Validate JSON online and see the exact line and column of any error. Auto-fix comments, trailing commas and single quotes. Free, in your browser.
How to use the JSON Validator Online
Validate, beautify and clean JSON, CSV, XML and YAML.
- Paste or upload your data
- Choose the options
- Copy or download the result
Tips
- Invalid JSON shows the exact line and column. “Auto-fix” repairs comments, trailing commas and single quotes.
- Numbers and key order are kept exactly as written – nothing is rounded.
- CSV: any delimiter is detected automatically; pick the one you want for the output.
- YAML: comments are kept, and you can convert YAML → JSON or paste JSON to get YAML.
Example
Input: {"name": "Ada",}
Output: Error at line 1, column 16: trailing comma. Auto-fix available.
Frequently asked questions
How do I check if my JSON is valid?
Paste it into the box. If it is valid you see it formatted. If not, the line, column and a pointer show the problem.
What does "Unexpected token" mean?
The parser found a character it did not expect, often a trailing comma, a missing quote or a comment. The error shows where.
Will large numbers change?
No. Unlike many tools, long numbers like 12345678901234567890 are kept as they are.
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