Salesforce -> PostgreSQL webapp integration, intermediate database

Hi,

We’re evaluating Zapier to pass data back and forth between Salesforce and a custom

webapp backed by a PostgreSQL database.  The data flow would look like this:

Salesforce <=> Zapier <=> PostgreSQL webapp database (Flow A)

The data flows in both directions. 

But, the page “How to Get Started with PostgreSQL”   https://zapier.com/help/doc/how-get-started-postgresql

includes this text:

Note: all fields are stored encrypted in our database. Of course, we
have the encryption keys on hand but they are stored separately to minimize
risk. Nonetheless, we recommend not hooking a production database to
Zapier. Instead, set up an intermediary database to connect with Zapier
then dump data back to your main production database using some out-of-band
process.

My reading of this is that we shouldn’t let Zapier talk to the webapp production database at all.

Rather, the data flow should look something like this:

Salesforce <=> Zapier <=> PostgreSQL intermediary database <=> PostgreSQL webapp database

(Flow B) 

In this case, Zapier would not be responsible for communication between the two Postgres

databases.

Unfortunately, we haven’t able to get 100% clarification on this issue from support or in the documentation.  We still have these questions:

1. Which is recommended, Flow A or Flow B?  Or in other words, should Zapier only talk to an intermediary database, or can it talk directly to a production database?
2. If Flow B is recommended, what are the risks of talking directly to the production database?
3. Is there any existing documentation that further explains why an intermediate database is necessary?
4. If Flow B is recommended, is Postgres replication considered an acceptable out-of-band process?

Thank you,

Alan