Create new C4C Web Services

We have a C4C tenant. We need to access data from that C4C tenant from another application. For that we need new web services in our C4C tenant. So far I only found documentation on how to extend views by e.g. adding new fields. I have not found any information on how to develop new web services, i.e. how to extend the API.

Is it possible and can you guide me please?

Kind Regards,

René