Ah, the no true microservices idea of webservice architecture. If the idea is that you code to a webservice interface and then providers implement that interface, well, you're going to end up with the same problem, but with different interfaces. If the client specifies the interface using GraphQL or the like, that moves the problem from the incompatible interface to incompatible data naming. And so on. You need global coordination to untangle a mess of interrelated services, or you need continual migration work to adapt from one team's implementation to another.