By default, PubNub does not store any published messages; messages are cleared off of the PubNub network cache after 12-16 minutes. PubNub offers message persistence for historical retrieval. Message retention policies include:
Our storage layer is a time-series based database. Each published message is timestamped to the nearest 10 nanoseconds. Messages are retrieved using the history API as part of the Storage & Playback feature. History takes in a channel name and one or more timestamps as the parameters, returning messages that meet the given criteria.
PubNub is Privacy Shield and HIPAA compliant, and also supports geographical limitations on where messages are stored. By default, messages are persisted to all available geographical locations.
For further learning, please see: