The Atlassian Jira Universal Avatar API allows developers to retrieve and manage user avatars from Jira Cloud and Jira Server instances. This API allows users to customize their avatars and provides a uniform way to access avatars across different platforms. With this API, developers can easily integrate avatars into their applications, providing a more personalized and engaging user experience. By utilizing the Universal Avatar API, developers can streamline avatar management and ensure consistency in avatar display across various platforms and devices.