The hardest part of connecting to MongoDB is getting the connection settings right. When connecting a new MongoDB account these are the fields you are presented with:
Host The IP address or hostname (db.example.com) of where your database instance resides. Make sure it is accessible from outside your network. We send out database connections from the IP addresses listed below.
Port 27071 is the default, change it if you're using a non-standard port.
Database Name of the database to read data out of.
Username Username with access to the database. We recommend creating a brand new Zapier-specific user with highly limited permission scope.
Password Similar to the username, make this a unique strong password (check out https://random.org).
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.