I can successfully create line items with website_conversions as the objective, but I noticed a couple of things:
IAB Categories:
I sent the id of a category “parent” instead of a category (ie. I sent “IAB11” instead of “IAB11-5” as the category) and the line item was created successfully. However, upon viewing the campaign details through the Twitter UI, I saw that the IAB category had not been set.
Primary Web Event Tag:
I used the tag id of an “UNVERIFIED” tag and the line item was created successfully. However, in the Twitter UI the dropdown to select a web even tag does not contain a tag and is disabled, so I cannot select a different tag.
Cost-Per-Conversion (target_cpa_local_micro):
My understanding is that the target_cpa_local_micro param corresponds to the cost-per-conversion in the Twitter UI (correct me if I’m wrong). The ads API documentation claims that this parameter is required for the WEBSITE_CONVERSIONS objective but I can successfully create a line item with website_conversions without this parameter. However, my real question is: when I do pass in a value for target_cpa_local_micro and successfully create a line item, the same campaign through the Twitter UI has a cost-per-conversion as 0 (as if it hadn’t been set).
If you could shed some light on these behaviours, it would be super helpful.