JSON Formatter & Validator — Free Online Tool

Paste your JSON below to format, validate, and beautify it instantly.

 
 
  
       
  
   
 
 
What is JSON?
 
JSON (JavaScript Object Notation) is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is widely used in web APIs, configuration files, and data storage.
 
How to Use This JSON Formatter
 
     
  1. Paste or type your JSON into the input area on the left
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  2. Click Format to beautify with indentation
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  3. Click Minify to compress into a single line
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  4. Click Validate to check if your JSON is valid
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  5. Click Copy Output to copy the result to your clipboard
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Features
 
     
  • Instant JSON formatting with 2-space or 4-space indentation
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  • JSON validation with detailed error messages and line numbers
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  • Minify JSON to reduce file size
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  • One-click copy to clipboard
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  • Works entirely in your browser — your data never leaves your device
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  • No signup, no limits, completely free
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Frequently Asked Questions
 
How do I format JSON online?
 
Paste your raw JSON into the input box and click "Format (2 spaces)" or "Format (4 spaces)". The formatted output appears instantly on the right. You can then copy it with one click.
 
How do I validate JSON?
 
Click the "Validate" button after pasting your JSON. If it's valid, you'll see a green success message. If there are errors, you'll get a detailed error message showing exactly what's wrong and where.
 
What is the difference between JSON format and minify?
 
Formatting adds indentation and line breaks to make JSON human-readable. Minifying removes all unnecessary whitespace to reduce file size — useful for production APIs and configuration files.
 
Is my JSON data safe?
 
Yes. This tool runs entirely in your browser using JavaScript. Your JSON data is never sent to any server — it stays on your device at all times.
 
Can I format large JSON files?
 
Yes. Since all processing happens locally in your browser, you can format JSON files of any size that your browser can handle — typically several megabytes without issues.
 
What JSON errors does this tool detect?
 
The validator catches all standard JSON syntax errors including missing commas, unmatched brackets, invalid strings, trailing commas, and incorrect data types. Error messages include the position of the problem.