> Can you clarify how you think Baker applies here?
"The conclusion to which we have come is, that blank account-books are not the subject of copyright; and that the mere copyright of Selden's book did not confer upon him the exclusive right to make and use account-books, ruled and arranged as designated by him and described and illustrated in said book." [1]
[1] https://supreme.justia.com/cases/federal/us/101/99/
My reading is that the mere use of an API is a method of practice. It does not matter if the API is simple or complex, in the same as it didn't matter if a single page or multiple pages of account templates were used.