JSON Formatting Best Practices for Developers

JSON (JavaScript Object Notation) is the backbone of modern web APIs. Whether you're building REST APIs, configuring applications, or storing data, proper JSON formatting is essential.

Common JSON Mistakes

1. Trailing Commas

Unlike JavaScript, JSON doesn't allow trailing commas:

// ❌ Invalid JSON
{
  "name": "John",
  "age": 30,
}

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

2. Single Quotes

JSON requires double quotes for strings:

// ❌ Invalid JSON
{'name': 'John'}

// ✅ Valid JSON
{"name": "John"}

3. Comments

JSON doesn't support comments. Remove them before parsing:

// ❌ Invalid JSON
{
  "name": "John" // user name
}

// ✅ Valid JSON
{
  "name": "John"
}

4. Unquoted Keys

All keys must be strings in double quotes:

// ❌ Invalid JSON
{name: "John"}

// ✅ Valid JSON
{"name": "John"}

JSON Formatting Guidelines

Use Consistent Indentation

Use 2 or 4 spaces for indentation. Be consistent across your project.

Keep Lines Short

For readability, avoid lines longer than 80-120 characters.

Order Properties Logically

Group related properties together. Consider alphabetical ordering for configuration files.

Use Meaningful Key Names

Choose descriptive, camelCase key names:

// ❌ Poor naming
{"fn": "John", "ln": "Doe"}

// ✅ Good naming
{"firstName": "John", "lastName": "Doe"}

Debugging JSON

Validate Before Parsing

Always validate JSON before using it in your application. Our JSON formatter tool highlights syntax errors instantly.

Use Pretty Print for Debugging

Minified JSON is hard to read. Format it when debugging:

// Minified (hard to debug)
{"users":[{"name":"John","age":30},{"name":"Jane","age":25}]}

// Pretty printed (easy to read)
{
  "users": [
    {"name": "John", "age": 30},
    {"name": "Jane", "age": 25}
  ]
}

Performance Tips

• Minify for production: Remove whitespace to reduce file size
• Use arrays for lists: Arrays are faster to parse than objects
• Avoid deep nesting: Flatten structures when possible
• Use numbers, not strings: {"age": 30} not {"age": "30"}