Are deadlocks possible in Akka ?
Well you can do terrible stuff in any library ;-)
It also depends what deadlock you mean – thread wise, if you only use right messaging APIs and never Await, then no, such will never happen.
A “state” deadlock can occur if you do your state wrong of course though. I.e. you become a state that “waits for a notification”, but you never send that notification… depending on how one views that situation, one could call it a “deadlock”, but such is simply some wrong logic and could happen in any library or tool or language.
In general: never await, never wait for things without timeouts. Then you’re safe.