After searching on the question, I have not been able to figure out: is it Possible to use the User Interface Export functions to get the Contact_ID number along with contact info? (the API has visibility of this ID)
Essentially, using the API is a bit overkill for what I need; I simply want to syncronize a couple internal databases I work with on our Constant Contact email info (along with other lists), and it would be very valuable for future syncronizations to have this Constant Contact Table Key stored. I only need to export this key along with the complete contacts export, and I would rather not have to dig in the JSON payload that the API returns, since what I really need is in CSV format.
Is this something that the UI supports, that I overlooked?
Unfortunately, this is not a function that is possible in the Constant Contact UI. For functions in the Constant Contact UI, the contact's email address is used as a primary key, unlike the API were we make use of a unique contact ID.
As you mentioned, it would be possible to create a CSV using the API data, however, it would be a very involved process where you would need to convert each contact's data to CSV format.
If there is anything that I can clarify, or provide assistance with, please let me know!