Validation Rules
Validation Results
Why Use a JSON Validator?
JSON validation ensures your data conforms to expected formats and structures, preventing errors before they reach production. Our free online JSON validator offers comprehensive syntax checking, JSON Schema validation, and automatic schema generation. Whether you're debugging API responses, validating configuration files, or ensuring data integrity, our tool provides detailed error messages and validation reports to help you identify and fix issues quickly.
Powerful Validation Features
Syntax Validation
Check JSON syntax for errors like missing brackets, commas, or quotes. Get precise error locations with line numbers.
Schema Validation
Validate JSON against JSON Schema standards (Draft 7 & 2019-09). Ensure data structure meets requirements.
Auto Schema Generation
Automatically generate JSON schemas from existing data. Create validation rules based on your JSON structure.
Custom Rules
Define custom validation rules for specific business logic. Combine schema and rule-based validation.
Common Validation Scenarios
- API Development: Validate API request and response payloads against defined schemas
- Configuration Files: Ensure JSON config files match expected structure before deployment
- Data Migration: Verify data integrity when migrating between systems or formats
- Third-Party Integration: Validate external data sources before processing
- Testing & QA: Automated validation in test suites to catch schema violations early
- Documentation: Generate schemas to document expected JSON structure for APIs
How to Validate JSON Online
- Input JSON: Paste your JSON data into the input panel or drag and drop a .json file
- Choose Validation Method: Select syntax-only, schema validation, custom rules, or combined validation
- Add Schema (Optional): Paste an existing schema or click "Generate Schema" to create one from your data
- Configure Rules (Optional): Add custom validation rules for specific field requirements
- Validate: Click "Validate JSON" or use Ctrl+Enter to run validation
- Review Results: Check validation results with detailed error messages, warnings, and success indicators
- Export Report: Download validation results for documentation or compliance purposes
Understanding JSON Schema
JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It describes your data format, providing clear documentation and validation rules.
- ✓ Type Validation: Ensure fields are strings, numbers, booleans, arrays, or objects
- ✓ Required Fields: Specify which properties must be present
- ✓ Format Validation: Validate email, URI, date-time, and other formats
- ✓ Range Constraints: Set minimum/maximum values for numbers and array lengths
- ✓ Pattern Matching: Use regex patterns to validate string content
- ✓ Nested Validation: Validate complex nested object structures