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Free Tool

JSON Formatter

Format, minify, and validate JSON. Free, fast, and works offline.

100% Free — No limits, works entirely in your browser

Input JSON

Quick Examples

Debugging API responses with minified JSON is painful. Unformatted JSON is unreadable, and finding syntax errors manually wastes hours of development time.

What This Tool Checks

  • Formats and beautifies JSON with proper indentation
  • Validates JSON syntax and highlights errors
  • Minifies JSON for production use
  • Shows line numbers and structure hierarchy
  • Handles large JSON files efficiently
  • Works completely offline in your browser

Who Should Use This Tool

  • Developers debugging API responses
  • Students learning about JSON and REST APIs
  • QA engineers testing backend responses
  • Anyone working with configuration files
  • Data analysts processing JSON datasets

Common Mistakes to Avoid

  • ✕Missing commas between object properties
  • ✕Using single quotes instead of double quotes
  • ✕Trailing commas after the last item
  • ✕Unescaped special characters in strings
  • ✕Not validating JSON before using in code

Frequently Asked Questions

JSON requires double quotes for all keys and doesn't allow trailing commas, functions, or undefined values. JavaScript objects are more flexible. JSON is for data exchange, JS objects are for programming.
Yes. This tool runs entirely in your browser—your JSON never leaves your device. No data is sent to any server. You can verify this by using the tool offline.
This usually means there's a syntax error—missing quotes, brackets, or commas. The tool will show you the exact line and position. Most common cause is forgetting to quote a property name.
Yes—Shift+Alt+F (Windows) or Shift+Option+F (Mac) formats the document. But this online tool is useful for quick formatting of API responses, config snippets, or sharing formatted JSON.
Processed locally
No data stored