I ask the same question. I use Vaadin extensively. What I really love about it is that I am able to code my frontend apps just like my backend microservices a

I ask the same question. I use Vaadin extensively. What I really love about it is that I am able to code my frontend apps just like my backend microservices apps... e.g. with Spring Boot. You can really leverage the years of experience in Java backend on your frontend. So far I have not ran into a problem I could not fix yet. Vaadin does have a learning curve. After using it for a while, I find myself wanting to use my own components, versus the many components Vaadin provides out of the box. Vaadin has support for PWA for single site apps. For multiple site apps, I had to create my own solution that relied heavily on Servlet Filters to dynamically return the PWA files. Vaadin has a really cool testing library. It makes it really easy for me to do TDD on my frontend code. TDD is a MUST. So I quickly create a breaking test using the Vaadin testing framework... which uses Selenium underneath the hood. Using Selenium is huge cause I can get answers to my questions about testing by searching for the Selenium answer that I can apply in my tests. Vaadin also supports PUSH technology out of the box. Its super easy to use. I use it extensively to have my web pages op up quickly, then slowly get filled out as the APIs return. No need to mention how awesome PUSH technology is. Though you need to be good at multi-threaded coding. FYI, I don't work for Vaadin. Plus I am also a REACT programmer. I love REACT and find it very elegant. I shed a tear first time I used REACT. I think REACT and Vaadin are similar for me (in the sense that I can get a lot of high quality work done quickly). For personal projects I will always use Vaadin. For paying clients, they typically request REACT.... lol.