API Security within the Hybrid Cloud

The Hybrid Cloud has 100s if not 1000s of APIs in use at any time. API security therefore becomes a crucial part of any hybrid cloud environment. There are only so many ways to secure an API, we can limit its access, check the commands, encrypt the data transfer, employ API level role based access controls, ensure we use strong authentication, etc. However, it mostly boils down to depending on the API itself to be secure because while we can do many things on the front end, there is a chance that once the commands and actions reach the other end (cloud or datacenter) that the security could be suspect. So how do we implement API security within the hybrid cloud today?