Generally the best advice is to conform to the SPOT (Single Point of Truth) rule as much as possible. For example, the place DEFINING users' addresses can be yo

Generally the best advice is to conform to the SPOT (Single Point of Truth) rule as much as possible. For example, the place DEFINING users' addresses can be your own database and the data in salesforce is only a REPLICATION of that data. And the DEFINITION of chats is in Intercom and you only have an API for RETRIEVING the data in your own code. It helps a lot when the "owners" of data are defined that way, because it's easy to reason about the flows. You can then have a set of APIs in your code for accessing (be it the master data/replicated data/live-fetched from an external system).