List asset versions

Name of the Variable. Used as the key for content personalization. Must be unique within the Asset Version. Example: firstName

Specifies the type of the Variable:

• value: A string value (default Variable type when not specified)
• asset: References another Asset by its Id
• externalUrl: References content at an external URL (must be publicly available)

Note: We recommend using asset type Variables instead of externalUrl for better consistency, security, compliance, and availability. External URLs might change without version control, may be subject to throttling, or could become unavailable.

Specifies how the Variable should be handled during rendering.

• optional: The Variable is optional and may or may not be provided in a request (such as create letter). If allowEmpty is true you can pass an empty string as its value.
• required: The Variable must be provided in a request (such as create letter). If allowEmpty is true you can pass an empty string as its value.
• preset: The preset value will be used and the variable should not be included in the request (such as create letter). The presetValue must be defined when this behavior is used. allowEmpty is not applicable to this behavior.
• overridablePreset: The preset value will be used, unless a value is explicitly passed in a request to override the preset value. The presetValue must be set when this behavior is used, and the variable can be included in a request if an override is necessary, otherwise the presetValue will be used. If allowEmpty is true you can pass an empty string as its value.

Note: When using Assets with Variables with our Letter API, always review the variableHandling option on the Letter. If validationScope is set to none in the request, the defined variables and their behavior will not be evaluated at all. See further information on the Letter object.

For detailed examples and edge cases on how behavior, allowEmpty, and presetValue interact, see the Assets Overview in our API reference.

Determines whether an empty value is acceptable for this Variable.

Example empty string: { "name": "firstName", "value": "" }

Note: null is considered as no value, not an empty one.

For detailed examples and edge cases on how behavior, allowEmpty, and presetValue interact, see the Assets Overview in our API reference.

Specifies a preset value for the Variable. This value may be used when:

• the Variable is not provided
• a value is provided but the behavior is set to presetValue

For detailed examples and edge cases on how behavior, allowEmpty, and presetValue interact, see the Assets Overview in our API reference.

Example: "ast_2k1UXnFem92yBFKxtTkQQYhVWyr"

Provides a sample value for the Variable, useful for documentation and UI purposes. This value is not used in the actual rendering process. It's primarily for demonstrating expected input in user interfaces or documentation.

Example: "Jane"