For the past six years, Oracle and Google have been embroiled in a lawsuit. Oracle claims that Android’s use of the Java Application program interface (APIs) constitutes copyright infringement.
At one point it looked like Google was going to have to pay Oracle almost $9 billion for using java’s interfaces in Android. This is a not a legal analysis of the case, but an analysis of what it means for APIs to be copyrightable.
First what is an API?
An API often includes specifications for routines, data structures, object classes, variables, or remote calls. For instance, an simple API for credit card processing might have two methods: verify credit card and charge credit card. Verify credit card would take a credit card number, expiration date, Card Verification Code (CVC) and returns a token or card denied. The charge credit card would take the token, an amount, charge the card and return a status of success or failure.
So an API is what you pass in and what you receive back in this simple example. If a number of credit card processing vendors implement the same API, you will be able to switch from one to another with only minor code changes. This prevents you from being locked into a vendor because you have written code against their interface and you do not want to pay to change the code.
APIs create common connections for code. Think of it as similar to common chargers for cell phones. This way when you buy a new phone you can reuse the cables and accessories. This allows consumers to have a better experience.
If APIs are copyrightable then no companies will be able to use the common APIs. This means that every time the company you are using changes, all the code will have to be rewritten. This means that companies will be locked into their vendor because they implemented their exclusive API and it will be too expensive to rewrite the code to use a different and better vendor.