JSON Validator
Validate JSON and show an error message if the input is invalid. Useful for debugging API responses and configuration files. Runs locally in your browser.
Input
Output
Tip: You can verify in DevTools → Network that nothing is uploaded.
About this JSON Validator
JSON Validator checks whether your input is valid JSON by attempting to parse it. If parsing fails, it reports the parser error so you can fix the first issue quickly.
This is useful when working with API payloads, configs, and logs. The validator targets strict JSON (no comments, no trailing commas).
- Process text data quickly without external tools
- Transform content for development workflows
- Clean and format text for analysis
- Enable Auto to transform as you type
- Upload text files directly from your device
- Download the result when done
FAQ
No. Everything runs locally in your browser. Nothing you paste is sent to a server.
After the page loads once, it will typically keep working offline (unless you hard refresh with no cache).
No. Your input stays in your browser. Only optional preferences like theme or language may be stored.
Any plain text. You can paste text directly into the input box.
JSON parsers stop at the first syntax error. Fix the first error and validate again to find any additional issues.
No. This tool validates strict JSON. Comments and trailing commas are not valid JSON and will cause errors.
No. Validation runs locally in your browser and nothing is uploaded to a server.