Via the API and settings > import, you can create a deal without any linked contact.
Via the interface, you cannot create a deal without a linked contact.
Are these 3 things all expected behavoiur, and if so what would be the reasoning for this?
Hi,
The following wiki might be useful to your scenario
https://devcommunity.pipedrive.com/t/importing-and-exporting-data/4963/2
Feel free to create a new topic if you are still facing challenges