Redis can publish an event when a key is set, expired or deleted, which looks like a way to trigger work — a session expiring firing a cleanup, say. It is pub/sub, and pub/sub is fire-and-forget.
CONFIG SET notify-keyspace-events Ex
PSUBSCRIBE '__keyevent@0__:expired'A subscriber that is not connected at the moment of the event never learns it happened, and there is no acknowledgement, no retry and no backlog. A deploy that restarts the workers loses every event during the gap. The expiry event has a second subtlety: it fires when the key is actually removed, which for a passively-expired key is when something next tries to read it, not when the TTL elapsed. Use a real queue for anything that must not be missed.