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JSON Formatter & Validator

The JSON Formatter & Validator is a powerful tool that helps you format, validate, and beautify JSON data. Whether you're working with API responses, configuration files, or any JSON data, this tool makes it easy to ensure your JSON is valid and readable.

Features​

  • Real-time Validation: Instantly detect syntax errors in your JSON
  • Customizable Formatting: Choose from different indentation levels (2, 4, 6, or 8 spaces)
  • Compact Mode: Minify JSON by removing all whitespace
  • Syntax Highlighting: Color-coded output for better readability
  • Error Detection: Clear error messages with details about what went wrong
  • Copy & Download: Easily copy formatted JSON or download it as a file
  • Auto-format on Paste: Automatically format JSON when pasting

How to Use​

  1. Input Your JSON:

    • Type or paste your JSON data into the left editor
    • The tool automatically validates and formats on input
    • If pasting, the tool will attempt to auto-format valid JSON

  2. Customize Format:

    • Use the "Indent Size" dropdown to adjust spacing (2-8 spaces)
    • Toggle "Compact Mode" for minified output
    • The right panel shows the formatted result in real-time

  3. Handle Results:

    • Click "Copy" to copy the formatted JSON to clipboard
    • Use "Download" to save the JSON as a file
    • If there are errors, they'll be shown below the editors

Common JSON Errors​

Missing Quotes Around Property Names​

{
  name: "John"  // Invalid
}

Should be:

{
  "name": "John"  // Valid
}

Trailing Commas​

{
  "name": "John",
  "age": 30,  // Invalid trailing comma
}

Should be:

{
  "name": "John",
  "age": 30  // Valid
}

Single Quotes​

{
  'name': 'John'  // Invalid
}

Should be:

{
  "name": "John"  // Valid
}

Invalid Values​

Valid JSON values include:

  • Strings (in double quotes): "hello"
  • Numbers: 42, 3.14
  • Booleans: true, false
  • null: null
  • Arrays: [1, 2, 3]
  • Objects: {"key": "value"}

Tips​

  1. Large JSON Files:

    • For better performance with large files, use the "Compact Mode" initially
    • Switch to formatted view once validated

  2. Working with APIs:

    • Use this tool to format and validate API responses
    • Helps identify issues in JSON structure before using the data

  3. Configuration Files:

    • Validate your JSON configuration files before deployment
    • Use the download feature to save properly formatted configs

  4. Error Handling:

    • Pay attention to error messages for quick problem resolution
    • Common issues include missing quotes and invalid commas

Technical Details​

The tool uses native JavaScript JSON.parse() and JSON.stringify() methods for validation and formatting, ensuring:

  • Standard-compliant JSON processing
  • No data loss during formatting
  • Reliable error detection
  • Cross-browser compatibility