In the guaranteed message delivery mode (aka "at-least-once" contract), undelivered messages are retained in the Realtime platform for a given period of time (so they can be re-delivered to subscribers as soon as possible).

After that period of time expires undelivered messages are permanently deleted and will not be re-delivered. 

For free subscriptions this retention time is 2 minutes and for paid subscriptions 3 days (72 hours).


Did this answer your question?