Is it possible to create custom fields via the API?
This question has been asked before:
but was answered in 2013 so i am wondering if there are any updates. It is difficult to transfer our CRM's data about leads to Marketo without an api (requires manual setup of several custom fields, that can be error prone, especially when we have several clients with separate marketo instances).
No, Marketo doesn't have an API for this right now. Try reaching out to Marketo support or your CSM, they might be able to help you out here.