Validate JSON format, check syntax errors, and format JSON online. Free, fast, and accurate JSON validation tool for developers.
JSON (JavaScript Object Notation) is a lightweight data interchange format that's easy for humans to read and write, and easy for machines to parse and generate. Our JSON validator helps ensure your JSON data is properly formatted and syntactically correct.
JSON validation checks whether a string is valid JSON format. This includes verifying proper syntax, correct use of brackets and braces, valid string formatting, and proper data type usage. Our validator provides instant feedback on any syntax errors.
The tool supports all standard JSON data types: strings, numbers, booleans, null, objects, and arrays. It also handles nested structures and complex data hierarchies commonly used in APIs and web applications.
JSON follows strict syntax rules that must be followed for valid data:
API Development: Ensure your API responses are valid JSON before sending to clients. Invalid JSON causes parsing errors in client applications and breaks integrations.
Data Processing: Validate JSON data before processing in applications. This prevents runtime errors and ensures data integrity throughout your system.
Configuration Files: Many applications use JSON for configuration. Validating these files prevents application startup errors and configuration issues.
Testing: Verify test data and mock responses are properly formatted JSON. This ensures your tests run correctly and provide accurate results.
Trailing Commas: JSON doesn't allow trailing commas in objects or arrays. Remove any comma after the last element.
Single Quotes: JSON requires double quotes for strings. Replace all single quotes with double quotes.
Unescaped Characters: Special characters in strings must be properly escaped with backslashes.
Missing Commas: Elements in objects and arrays must be separated by commas.
Use consistent indentation (2 or 4 spaces) for better readability. Our formatter automatically applies proper indentation to make your JSON more readable.
Keep object keys short but descriptive. Use camelCase for JavaScript compatibility or snake_case for consistency with other systems.
Validate JSON before using in production applications. Our validator catches syntax errors that could break your application.
Common causes of invalid JSON include: using single quotes instead of double quotes, trailing commas, unescaped special characters, missing commas between elements, and using undefined or NaN values. Our validator identifies these issues and provides specific error messages.
Yes, our JSON validator can handle large JSON files. The tool processes JSON data efficiently and provides validation results for files of any reasonable size. For very large files, the formatting feature may take a moment to process.
JSON is a text format that follows strict syntax rules, while JavaScript objects are programming constructs. JSON requires double quotes for strings, doesn't allow trailing commas, and has limited data types. JavaScript objects are more flexible but not always valid JSON.
Yes, our JSON validator is completely free to use. No registration or download required. You get instant, accurate JSON validation and formatting without any limitations. Use the tool as many times as you need without restrictions or costs.
Our JSON validator provides highly accurate results following the official JSON specification (RFC 7159). The tool catches all syntax errors and validates against standard JSON rules, making it suitable for professional development, API testing, and data validation.
Yes, the JSON validator works perfectly on all mobile devices. The responsive design adapts to your screen size automatically. Whether you use a smartphone, tablet, or desktop computer, you get the same fast, accurate validation without any app installation.
