> For the complete documentation index, see [llms.txt](https://docs.bird.com/api/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bird.com/api/contacts-api/api-reference/manage-contact-attribute-definition.md).

# Manage contact attribute definition

## Attributes

Attributes in the Bird Contacts API are flexible pieces that contain detailed information about a contact, enabling businesses to store and manage customer-specific details beyond basic identifiers and properties. These attributes can include customizable fields tailored to fit unique business requirements, such as subscription preferences or transaction-related data.

### API Reference Guide <a href="#api-reference-guide" id="api-reference-guide"></a>

1. [Create attribute definition](/api/contacts-api/api-reference/manage-contact-attribute-definition/create-attribute-definition.md)
2. [Get attribute definitions](/api/contacts-api/api-reference/manage-contact-attribute-definition/get-attribute-definition.md)
3. [List attribute definitions](/api/contacts-api/api-reference/manage-contact-attribute-definition/list-attribute-definitions.md)