I have been using vertx for many years and think it is one of the greatest libraries for networked applications. I created a course that is live on udemy to help devs get into backend development with vert.x or anyone trying to level up in general. The course uses kotlin as its primary language too I hope many of you here would find it useful and interesting. It contains 5.5 hours of video content talking about concepts and code both https://www.udemy.com/course/backend-development-with-vertx/?referralCode=063C2D57CCB957C5088C