The XAF Framework, or eXpressApp Framework, is a software development framework created by DevExpress that simplifies the process of building business applications. It provides a set of tools and libraries that help developers create user interfaces, manage data, and implement business logic efficiently. XAF supports various data storage options, including SQL Server and Oracle, and allows for rapid application development through its model-driven architecture. This means developers can focus on defining the application's structure and behavior rather than writing extensive code, making it easier to maintain and extend applications over time.