AngularJS is a structural framework for dynamic web applications, developed and maintained by Google. It allows developers to use HTML as the template language and extends HTML's syntax to express the application’s components clearly and succinctly. AngularJS aims to simplify both development and testing of web applications by providing a framework for client-side model–view–controller (MVC) and model–view–view model (MVVM) architectures, along with components commonly used in rich internet applications.