> You don't need to build a facade for every api client (the api client is already a facade).

I feel like this is covered by

> Every rule and principle can be broken once you’ve fully understood its purpose. For example if an object already does have an idiomatic API, it’s probably not worth wrapping in an identical façade, just so it belongs to you.

?

I personally prefer pytest-httpserver that is a bit more low-level, but I still prefer idiomatic calls over sprinkled http requests on business code.