JSON Validator
One trailing comma in a config file can stop an application from starting. This tool checks JSON syntax line by line, explains each error location, and runs fully in your browser. Do not paste production keys; use sample values.
Step by step
- Copy the suspicious config content.
- Paste it into the text area.
- Click Validate and read the result.
- Go to the reported line and fix the comma or quote.
- Validate again until the file passes.
Example scenario
A translation file often has a trailing comma after the last entry. Pasting shows the unnecessary comma before the closing brace. Delete it and validate again for a valid result. Use demo values, not real API keys.
Check your result
After validation passes, test the file in a staging environment. Look before the flagged line too. Review the final file for secrets before committing.
Frequently asked questions
Schema checks?
No, syntax only.
Why do comments error?
Standard JSON has no comments.
Single quotes?
No, JSON requires double quotes.
BOM issues?
Sometimes. Save as UTF-8 and remove it.
Open the tool: JSON Validator →
Keep an original copy before processing your file. Examples are illustrative; results depend on your document.