Copyleft should not extend to APIs
By Richard Fontana

In Oracle v. Google a U.S. appellate court held that APIs (specifically, the Java SE APIs) were copyrightable. The result is in conflict with previous collective expectations in the software industry and with European decisions like SAS Institute v. World Programming. But the result in Oracle v. Google is already having some impact on copyleft policy. Early drafts of one recent copyleft license, the Cryptographic Autonomy License (the subject of a CopyleftConf 2019 talk) featured an attempt to explicitly apply copyleft to mere use of APIs. At the same time, some have argued, in effect, that API copyrightability is a beneficial legal result for supporters of existing strong copyleft licenses like the GPL.

This talk argues that, as a matter of free software/open source licensing policy and license interpretation, copyleft should not be extended to cover mere copying or use of APIs, even where jurisdictions have explicitly recognized API copyrightability. Existing copyleft licenses like those of the GPL family should not be re-interpreted to subject APIs to copyleft conditions. Moreover, drafters of new copyleft licenses should not attempt to impose copyleft requirements on the use of APIs. Indeed, new copyleft licenses should explicitly exclude APIs as such from copyleft.