So the API in the States are copyrighted matter, following to US Supreme Court denial of a certiorari asked by Google?
TL;DR: probably not

https://www.eff.org/deeplinks/2015/06/bad-news-supreme-court-refuses-review-oracle-v-google-api-copyright-decision

Background.

In Europe SAS Institue v. World Programming Language set the law saying that copyright will not apply to programming languages, file formats, API. So far it’s the decision going farthest in the world to create an interoperability exception to copyright.

In USA the same issue arose first in Lotus v. Borland, which has set the rule so far, similarly to what the SAS case did in Europe. Recently the issue was on the table in the Ninth Circuit, in the case Oracle v. Google, dealing with the copyright in certain Java classes replicated in Dalvik (one of the buiding blocks of Android). Judge Allsup decided largely in favor of Google, Oracle appealed, the Court of Appeal for the Federal Circuit (CACFC) remanded and incidentally ruled that Oracle had the right to claim copyright in those API.

Google applied for /certiorari/ which is an application to the SCOTUS to correct an error in the law made by the lower courts before it spreads. The SCOTUS denied it.

Discussion

Many argue that this refusal can open the floodgates to litigation against those who implement a third party API, if API were considered indeed copyrighted matter, rather than functional in nature and thus outside the scope of copyright. Which would be disastrous, I agree.

However, things are very strange procedurally, and a high authority which I cannot disclose (Eben Moglen) thinks different, and has written it in the amicus brief he wrote for SFLC. http://softwarefreedom.org/resources/2014/google_v_oracle-sflc_cert_amicus.pdf

I am quite confident that this would summarize the situation rather correctly, and I leave it to the more learned discussant to say if I’m wrong or right.

This is a very peculiar bit of a litigation where the CAFC has taken a somewhat flawed approach, where the discussion revolves around very peculiar facts, and whose outcome is not likely to change very much the case as remanded to the Ninth Circuit, never mind the law applying to API. By denying the certiorari, the Supreme Court has just exerted their right not to care about cases which have no real impact on the law.

The decision, as far as we can tell, is based onjust because“. In particular, there is no conclusion to be made from this refusal as to the correctness of the positions of the parties and the likelihood that the Supreme Court will or will not uphold them should a case on the same subject matter come again to the attention of the Supreme Court.

So, while the decision leaves an open wound, it is likely that this wound is a very light one. And that law on API remains the one we know since Louts v. Borland, as the CAFCT case does not have any impact.

I’m not expert in US law and litigation, but I submit that this could be less problematic than it would seem upfront.

So keep calm and carry on interoperating.