GWT vs Preact: What are the differences?
Developers describe GWT as "*An open-source set of tools to create and maintain complex JavaScript front-end applications *". It is a development toolkit for building and optimizing complex browser-based applications. Its goal is to enable productive development of high-performance web applications without the developer having to be an expert in browser quirks, XMLHttpRequest, and JavaScript. On the other hand, Preact is detailed as "Fast 3kb alternative to React with the same ES6 API". Preact is an attempt to recreate the core value proposition of React (or similar libraries like Mithril) using as little code as possible, with first-class support for ES2015. Currently the library is around 3kb (minified & gzipped).
GWT belongs to "Javascript MVC Frameworks" category of the tech stack, while Preact can be primarily classified under "Javascript UI Libraries".
Preact is an open source tool with 23.3K GitHub stars and 1.23K GitHub forks. Here's a link to Preact's open source repository on GitHub.
Resource Guru, Bustle, and VN2RAP are some of the popular companies that use Preact, whereas GWT is used by LTE Consulting, Whatfix, and Unmetric. Preact has a broader approval, being mentioned in 16 company stacks & 39 developers stacks; compared to GWT, which is listed in 7 company stacks and 5 developer stacks.