[nradov]

Never say never. It's generally impossible to predict how an API will have to evolve over time in response to changing requirements.

[smizell]

That's true. However, I think this falls under YAGNI [0]. If you happen to get to a point where you have to change your an entire API rather than evolve what you have, you should consider it a new, separate API rather than instruct all client developers to plan for it up front. Plan for evolvability and handling changing requirements up front.

[0] https://martinfowler.com/bliki/Yagni.html

[ljcrabs]

And how would you name this new API? Bob? Or version 2?

[smizell]

Name it whatever you want. Point is, you don't have to plan for such a drastic change when a separate domain/subdomain will solve it for you.