Can I use it with Vue?

Short answer: Not exactly—it depends on how determined you are. Successful implementations in Vue have already been achieved, but these are not straightforward endeavors.

As of today, Keycloakify is primarily a React framework.

While Keycloakify as a build tool is agnostic to the frontend framework, it also includes a library of React components that are direct translations of the default theme. Reimplementing these components from scratch is not an easy task.