> In practice this might mean reading the API documentation and writing 20 lines of code per endpoint - not a deal breaker for me.

On this note, I have found Elixirs built in Task/GenServer/Process/Supervision primitives [sic] (also GenStage!) to be immensely useful when corralling diverse APIs. It's very easy to break each part into its own tiny system and link together, handle fails, backoff, etc.