In reply to Jeffr0.

Sorry, @mark k., but you are completely wrong about the Google vs Oracle case. I think you must be talking about the original trial verdict and not the subsequent appeal.

In fact, the Court of Appeals for the Federal Circuit has held that APIs can be subject to copyright. You can read the full law report here: https://scholar.google.com/scholar_case?q=google+oracle&hl=en&as_sdt=40006&case=15197092051369647665&scilh=0

Google did petition the Supreme Court, but the latter declined to take the case, so the appeals court's holding is what currently states US law.

Google might still succeed in a trial on the facts, if it can establish fair use. But, as Google itself recognizes, a win on those terms would be very different from winning on the basis that an API cannot be subject to copyright at all.