JSON Validator Online Free - Validate & Format JSON
Validate JSON syntax instantly with our free online JSON validator. Find errors, format messy JSON, and ensure API compatibility. Perfect for developers debugging APIs, configuration files, and data structures.
ℹ️ Did you know? Invalid JSON causes 40% of API integration failures. Validating JSON before deployment prevents request errors, saves debugging time, and ensures smooth data exchange.
Why Validate JSON?
Catch Syntax Errors: Find missing commas, unclosed brackets, or quote mismatches that break API calls and data parsing.
API Development: Ensure request/response payloads match API specifications before sending to production servers.
Configuration Files: Validate package.json, tsconfig.json, and other config files to prevent build failures.
Common Use Cases
- API Testing: Validate REST API responses before processing
- Configuration: Check package.json, settings.json validity
- Data Migration: Ensure JSON exports are properly formatted
- Debugging: Identify syntax errors in complex nested structures
- Code Review: Verify JSON strings in code before deployment
📝 Example: API Response Validation
Developer testing API endpoint:
- Issue: API returns 500 error
- Action: Paste response into validator
- Found: Missing comma on line 12
- Fix: Correct JSON, API works perfectly
Features
- Syntax Validation: Instant error detection with line numbers
- Auto Format: Beautify messy JSON with proper indentation
- Minify: Remove whitespace for production use
- Error Messages: Clear explanations of what's wrong
💡 Pro Tip: Use "Format" to make JSON readable, "Minify" to reduce file size for production. Always validate before deploying to catch errors early.
Common JSON Errors
- Missing or extra commas
- Unescaped quotes in strings
- Trailing commas (not allowed in JSON)
- Single quotes instead of double quotes
- Unclosed brackets or braces