Indentation Standards for Formatted JSON

JSON (JavaScript Object Notation) is a lightweight data-interchange format. While its structure relies on keys, values, arrays, and objects, the visual presentation—specifically indentation—plays a critical role in making JSON data human-readable and manageable. Consistent indentation isn't strictly required for JSON parsers, but it is essential for anyone working with the data.

Why Indentation Matters

Proper indentation significantly improves the readability of JSON data, making it easier to understand the hierarchical structure at a glance.

Common Indentation Standards

While there isn't one single official standard for *how* to indent JSON, common practices have emerged that tools and developers generally follow.

1. Spaces vs. Tabs

This is a perennial debate in programming, and JSON is no exception.

• Spaces: Using spaces ensures that the indentation looks the same regardless of the editor or its configuration. This consistency is often preferred.
• Tabs: Tabs allow developers to set their preferred visual indentation width in their editor. However, mixing spaces and tabs can lead to alignment issues if editors are not configured consistently.

Most modern JSON formatters and linters default to using spaces.

2. Number of Spaces

If spaces are used, how many per indentation level?

• 2 Spaces: A compact option that saves vertical space, especially for deeply nested structures.
• 4 Spaces: A more traditional and widely adopted standard across many programming languages, providing clearer visual separation.

Both 2 and 4 spaces are common. The key is to choose one and stick to it within a project or team.

Examples of Indentation

Let's look at the same JSON data with different indentation styles.

{"name":"Product","id":123,"tags":["electronic","gadget"],"details":{"price":99.99,"inStock":true}}

{
  "name": "Product",
  "id": 123,
  "tags": [
    "electronic",
    "gadget"
  ],
  "details": {
    "price": 99.99,
    "inStock": true
  }
}

{
    "name": "Product",
    "id": 123,
    "tags": [
        "electronic",
        "gadget"
    ],
    "details": {
        "price": 99.99,
        "inStock": true
    }
}

{
	"name": "Product",
	"id": 123,
	"tags": [
		"electronic",
		"gadget"
	],
	"details": {
		"price": 99.99,
		"inStock": true
	}
}

Tools for Formatting JSON

Fortunately, you don't have to manually indent JSON. Many tools and software libraries can automatically format JSON data according to your chosen standard (usually spaces, with a configurable width).

Best Practices

• Agree on an indentation style (spaces vs. tabs, number of spaces) within your team or for your personal projects.
• Use automated formatters integrated into your workflow (editor settings, pre-commit hooks) to ensure consistency.
• Format your JSON before committing it to version control.
• Only use minified JSON for transmission or storage where space is critical and human readability is not required.

Conclusion

While the JSON specification itself is lenient about whitespace, adopting and consistently applying a clear indentation standard is crucial for anyone who needs to read or maintain JSON data. Using automated tools to format your JSON ensures that your data is not only valid but also consistently readable, reducing errors and improving collaboration. Choose a standard that works for you or your team, and make formatting a regular part of your development process.