What is JSON Null?

In JSON, null is used to represent the absence of a value. It is a special value that indicates a key has no associated data or that the value is intentionally empty.

For example:

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{
  "name": null
}

In this example, the key "name" is present, but it explicitly holds no value.

Syntax Rules for JSON Null

  • No Quotes: The value null must not be enclosed in quotes. If quotes are added, it will be treated as a string.
  • Lowercase Only: The value null must always be written in lowercase.
  • Standalone Value: null can only appear as a value, not as a key.

Examples of JSON Null

1. Key with a Null Value:

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{
  "age": null
}

2. Null in an Array:

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{
  "values": [1, 2, null, 4]
}

3. Nested Object with Null:

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{
  "user": {
    "name": null,
    "email": "user@example.com"
  }
}

Common Use Cases for JSON Null

  • Missing Data: Use null to indicate that a value is missing or not available.
  • Optional Fields: Represent fields that are not required or yet to be filled.
  • Resetting Values: Use null to explicitly clear or reset a value in applications.
  • Database Integration: Represent NULL values from databases in JSON responses.

Tips for Using JSON Null

  • Ensure that null is used intentionally and not as a placeholder for unknown values.
  • Be cautious when parsing null in different programming languages, as its handling may vary.
  • Validate JSON to ensure proper usage of null.