Developer Tools

JSON Validator & Formatter

Paste your JSON to validate, format, and analyze. Get detailed error messages with line and column positions for invalid data.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format. It is easy for humans to read and write, and easy for machines to parse and generate.

Features

• Validate JSON syntax instantly
• Format with 2-space indentation
• Count lines and keys
• Detailed error position info
• Copy formatted output

What counts as valid JSON?

Valid JSON must be a properly structured object, array, string, number, boolean, or null. Objects use curly braces with key-value pairs, arrays use square brackets, and strings must be double-quoted.

Can I validate nested JSON?

Yes. The validator handles deeply nested objects and arrays. The key count includes all keys at every nesting level.

Is my data processed on a server?

No. All validation and formatting happens entirely in your browser. Your data never leaves your device.