# Catalog Custom Attribute Definition

Contains information defining a custom attribute. Custom attributes are
intended to store additional information about a catalog object or to associate a
catalog object with an entity in another system. Do not use custom attributes
to store any sensitive information (personally identifiable information, card details, etc.).
[Read more about custom attributes](https://developer.squareup.com/docs/catalog-api/add-custom-attributes)

## Structure

`CatalogCustomAttributeDefinition`

## Fields

| Name | Type | Tags | Description |
|  --- | --- | --- | --- |
| `type` | [`string`](../../doc/models/catalog-custom-attribute-definition-type.md) | Required | Defines the possible types for a custom attribute. |
| `name` | `string` | Required | The name of this definition for API and seller-facing UI purposes.<br>The name must be unique within the (merchant, application) pair. Required.<br>May not be empty and may not exceed 255 characters. Can be modified after creation.<br>**Constraints**: *Minimum Length*: `1`, *Maximum Length*: `255` |
| `description` | `string \| null \| undefined` | Optional | Seller-oriented description of the meaning of this Custom Attribute,<br>any constraints that the seller should observe, etc. May be displayed as a tooltip in Square UIs.<br>**Constraints**: *Maximum Length*: `255` |
| `sourceApplication` | [`SourceApplication \| undefined`](../../doc/models/source-application.md) | Optional | Represents information about the application used to generate a change. |
| `allowedObjectTypes` | [`string[]`](../../doc/models/catalog-object-type.md) | Required | The set of `CatalogObject` types that this custom atttribute may be applied to.<br>Currently, only `ITEM`, `ITEM_VARIATION`, `MODIFIER`, `MODIFIER_LIST`, and `CATEGORY` are allowed. At least one type must be included.<br>See [CatalogObjectType](#type-catalogobjecttype) for possible values |
| `sellerVisibility` | [`string \| undefined`](../../doc/models/catalog-custom-attribute-definition-seller-visibility.md) | Optional | Defines the visibility of a custom attribute to sellers in Square<br>client applications, Square APIs or in Square UIs (including Square Point<br>of Sale applications and Square Dashboard). |
| `appVisibility` | [`string \| undefined`](../../doc/models/catalog-custom-attribute-definition-app-visibility.md) | Optional | Defines the visibility of a custom attribute to applications other than their<br>creating application. |
| `stringConfig` | [`CatalogCustomAttributeDefinitionStringConfig \| undefined`](../../doc/models/catalog-custom-attribute-definition-string-config.md) | Optional | Configuration associated with Custom Attribute Definitions of type `STRING`. |
| `numberConfig` | [`CatalogCustomAttributeDefinitionNumberConfig \| undefined`](../../doc/models/catalog-custom-attribute-definition-number-config.md) | Optional | - |
| `selectionConfig` | [`CatalogCustomAttributeDefinitionSelectionConfig \| undefined`](../../doc/models/catalog-custom-attribute-definition-selection-config.md) | Optional | Configuration associated with `SELECTION`-type custom attribute definitions. |
| `customAttributeUsageCount` | `number \| undefined` | Optional | The number of custom attributes that reference this<br>custom attribute definition. Set by the server in response to a ListCatalog<br>request with `include_counts` set to `true`.  If the actual count is greater<br>than 100, `custom_attribute_usage_count` will be set to `100`. |
| `key` | `string \| null \| undefined` | Optional | The name of the desired custom attribute key that can be used to access<br>the custom attribute value on catalog objects. Cannot be modified after the<br>custom attribute definition has been created.<br>Must be between 1 and 60 characters, and may only contain the characters `[a-zA-Z0-9_-]`.<br>**Constraints**: *Minimum Length*: `1`, *Maximum Length*: `60`, *Pattern*: `^[a-zA-Z0-9_-]*$` |

## Example (as JSON)

```json
{
  "type": "STRING",
  "name": "name0",
  "description": "description0",
  "source_application": {
    "product": "BILLING",
    "application_id": "application_id8",
    "name": "name2"
  },
  "allowed_object_types": [
    "CATEGORY",
    "IMAGE"
  ],
  "seller_visibility": "SELLER_VISIBILITY_HIDDEN",
  "app_visibility": "APP_VISIBILITY_HIDDEN",
  "string_config": {
    "enforce_uniqueness": false
  }
}
```