Paste broken JSON or YAML. We auto-repair the common mistakes and, if anything's still wrong, point at the exact line and column. Everything runs in your browser.
Once your JSON is clean, turn it into a live mock REST API you can call, then make it fail on purpose to test your error handling.
Mock this as a live APIThe repair pass handles the mistakes that break JSON most often, then validates the result so you know it's actually parseable.
| Problem | Fix |
|---|---|
Trailing commas [1,2,] | Removed |
Single quotes 'value' | Converted to double quotes |
Unquoted keys {name:1} | Keys quoted |
Comments // … and /* … */ | Stripped |
Python/JS literals True False None NaN undefined | Mapped to true false null |
Smart quotes “ ” | Straightened |
If something can't be auto-fixed (a missing bracket, a misplaced value), the validator shows the exact line and column with a caret under the problem so you can fix it fast.
No. Repair and validation run entirely in your browser. Nothing is sent anywhere.
Paste the JSON and hit Repair. The most common causes are trailing commas, single quotes, and unquoted keys, which are all fixed automatically. For structural problems, the validator points at the exact spot.
Switch the format to YAML. We validate it, normalize the formatting, and pinpoint the line and column of any syntax error.