Instantly validate JSON syntax, find errors with exact line numbers, and ensure your JSON is well-formed. Free, fast, and secure.
Copy your JSON data and paste it into the input editor. The validator accepts any JSON content.
Click "Format" or "Validate" to check syntax. Errors are highlighted with the exact line and position.
Fix the highlighted errors, then format your JSON for clean, readable output.
{ "name": "John", "age": 30, }{ "name": "John", "age": 30 }{ 'name': 'John' }{ "name": "John" }{ name: "John" }{ "name": "John" }{ "name": "John" // comment }{ "name": "John" }Note: JSON does not support comments. Use JSONC or JSON5 if you need comments.
Our JSON Validator instantly checks your JSON for syntax errors. Missing commas, unclosed brackets, invalid strings - all errors are detected immediately and displayed with their exact line and character position so you can fix them quickly.
We perform strict validation according to the JSON specification (RFC 8259). This ensures your JSON will work correctly with any standards-compliant parser in any programming language or platform.
When an error is found, we don't just say "Invalid JSON." Our validator provides descriptive error messages explaining exactly what's wrong, along with the line number and character position where the error occurred.
Since all validation happens in your browser using JavaScript, you can use this tool even without an internet connection. Once the page is loaded, validation works entirely offline with no server communication required.
Perfect for debugging API responses that return unexpected errors. Paste the raw response to quickly check if the JSON is valid and identify any syntax issues that might be causing parsing failures in your application.
Your JSON data never leaves your browser. All validation is performed locally using client-side JavaScript. This makes it completely safe to validate sensitive data, credentials, and private configurations.