GWT, or Google Web Toolkit, is an open-source development toolkit that makes it easier for developers to create and maintain complex JavaScript front-end applications. GWT allows developers to write client-side Java code and have it compiled into optimized JavaScript that runs across all major browsers. GWT also provides an integrated development environment (IDE) with debugging capabilities, performance optimization, and other features that make development faster and easier. With GWT, developers can quickly create complex web applications that are highly optimized and perform well across different platforms and devices. The GWT community is large and active, and the project is backed by Google, making it a great choice for developers looking for a reliable and powerful development toolkit.