We found this post from 2018: https://forum.ftrack.com/topic/1325-how-to-create-new-entity-types-with-python-api/

Back then, it was not possible. Is it possible now? Inside the API reference, we see types such as:

• CustomAttributeType
• Type
• etc

Can I add new ones of these via the API?

If not, that's something we'd really like to request. We have multiple Ftrack environments, and would like to keep them in sync. It is our number one source of error today when we go from staging to production.

Ideally we're trying to make some kind of "migration script" framework where we (as part of a feature branch) can have code that adds new custom attributes or types as needed, and then (in that way) keeps it in sync.