JSON Validator
Validate JSON syntax and catch errors
About this Tool
JSON Validator is a free, privacy-first tool built for developers. Validate JSON syntax and catch errors
All processing in your browser
Instant results, no delays
No signup, no limits
Upload or paste content
Saved locally for quick access
Disclaimer
This tool is provided for informational and educational purposes only. All processing happens entirely in your browser - no data is sent to our servers. While we strive for accuracy, please verify critical data before use in production environments. FormatKit is not responsible for any data loss, corruption, or issues resulting from tool usage.
How to Use JSON Validator
Upload a JSON file or paste your JSON into the text area and the validator will check it in real-time. Any syntax errors will be highlighted with clear error messages.
Features
- Real-time validation as you type
- Detailed error messages with line/column information
- Character count display
- Pretty-print valid JSON automatically
- Copy validated JSON with one click
Common Use Cases
- Pre-deployment validation: Catch JSON errors before pushing configuration to production
- API development: Validate JSON payloads before sending to endpoints
- Data quality checks: Ensure JSON data files are properly formatted
- Learning: Understand common JSON syntax errors and how to fix them
FAQ
Q: What types of errors does the validator catch?
The validator detects all JSON syntax errors including missing brackets, trailing commas, unquoted keys, invalid escape sequences, and more.
Q: Can I validate JSON Schema?
JSON Schema validation is planned for a future update. Currently, the tool validates JSON syntax only.
Q: Is there a size limit?
No hard limit, but very large files (10MB+) may cause performance issues. For optimal performance, keep files under 5MB.