Facebook has introduced the "action_source" parameter into Conversions API, which for most use cases will be "website" for the value. Are we able to optimize toward conversions we send in this manner for values other than "website"?
For example, let's say that we currently drive people toward a page where we collect their information and then call them over the phone to finalize the order. We could send that final order as a conversions API purchase event with action_source="phone_call" and we'd like to optimize our ads toward the finalized order if possible.
Yes you can optimize toward conversions API events with any action_source except "physical_store" and "app" (as of May 2021). You can see a list of action_source values here: https://developers.facebook.com/docs/marketing-api/conversions-api/parameters/server-event#action-source
Keep in mind, that if you use "website" as the action_source you will also need to pass client_user_agent and event_source_url to comply with privacy protecting policies.