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JSON Formatter & Validator

A free online tool for validating and formatting JSON data.

?JSON을 입력하세요

📝 입력 JSON

줄: 0문자: 0크기: 0 bytes

✨ 결과

JSON (JavaScript Object Notation)의 유효성을 검사하고 포맷팅합니다. 들여쓰기를 추가하여 가독성을 높이거나, 공백을 제거하여 크기를 줄일 수 있습니다.

What is JSON?​

JSON (JavaScript Object Notation) is a lightweight data interchange format. It's easy for humans to read and write, and easy for machines to parse and generate. It's widely used in web APIs, configuration files, and data storage.

Key Features​

  • Validation: Real-time detection of JSON syntax errors
  • Formatting (Prettify): Improve readability with indentation
  • Compression (Minify): Reduce size by removing whitespace
  • Real-time Statistics: Display line count, character count, and byte size
  • Indentation Settings: Choose 2/4/8 spaces
  • Sample Load: Quick testing with example JSON

How to Use​

JSON Validation​

  1. Paste JSON into the input area
  2. Validation happens in real-time
  3. Detailed error messages are displayed if errors exist

JSON Formatting​

  1. Enter your JSON
  2. Select indentation size (2/4/8 spaces)
  3. Click the "Format" button
  4. Formatted JSON is displayed

JSON Compression​

  1. Enter your JSON
  2. Click the "Minify" button
  3. Single-line JSON with whitespace removed is output

Common JSON Errors​

1. Trailing Comma​

// ❌ Wrong
{
  "name": "John",
  "age": 30,  ← trailing comma
}

// ✅ Correct
{
  "name": "John",
  "age": 30
}

2. Missing Quotes​

// ❌ Wrong
{
  name: "John"  ← no quotes on key
}

// ✅ Correct
{
  "name": "John"
}

3. Single Quotes​

// ❌ Wrong
{
  'name': 'John'  ← single quotes
}

// ✅ Correct
{
  "name": "John"
}

Use Cases​

1. API Response Debugging​

Format API responses to easily identify structure and values.

2. Configuration Files​

Create and validate configuration files like package.json, tsconfig.json.

3. Data Storage​

Validate JSON before storing in local storage or databases.

4. Log Analysis​

Parse and analyze structured logs.

5. Test Data​

Generate mock data for testing.

Frequently Asked Questions​

Q: Can I add comments to JSON?​

Standard JSON doesn't support comments. Alternatives:

  • JSONC: JSON with Comments (used in VS Code)
  • JSON5: Supports JavaScript-style comments

Q: What's the maximum JSON size?​

No theoretical limit, but practically:

  • Browser: About 10-100 MB (varies by browser)
  • Node.js: About 512 MB (V8 engine default)
  • Memory limit: Depends on system memory

Q: How do I represent dates in JSON?​

Standard method is ISO 8601 string:

{"date": "2022-01-01T00:00:00.000Z"}

Q: What's the difference between undefined and null?​

  • null: Valid value in JSON
  • undefined: Not supported in JSON (omitted or converted to null)

Q: Does formatting slow down performance?​

Slightly slower but negligible. Use formatting during development, minification in production.

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Feel free to send us your feedback or suggestions anytime!

Privacy​

This tool operates entirely on the client side. Your JSON data is never sent to a server and is processed only in your browser.