This page lists all of the places to ask for help or discuss Javalin, in order of relevance.
The GitHub repo (https://github.com/javalin/javalin) is where most of the action happens. You can create issues to make feature request, to report bugs, or even to ask questions. We're not too strict.
Discord is the primary chat server for Javalin. You can use this invite link to join: https://discord.com/invite/sgak4e5NKv.
It's not as lively as Discord, but it is a lot more corporate: https://javalin-io.slack.com/
Javalin doesn't tweet a lot, but it does retweet and like Javalin related things: https://twitter.com/javalin_io
Javalin has its own tag on Stack Overflow, but it's not a common place to seek help: https://stackoverflow.com/questions/tagged/javalin