Headless development is a type of web development where the user interface (UI) is not rendered in a browser. Instead, the code is written to create a server-side application that serves its data in a format that can be consumed by other applications. Headless development allows developers to focus on the data and logic of the application, rather than the design of a user interface. This approach can be used to create applications that are more efficient and secure, as the user interface is not exposed to the public.