Can an API be licensed?
<p>My question is this simple - can an API (Application Programming Interface) be licensed? How does such licensing work? I mean, to have the source/binary licensed under one licence and the API under another one (or even the same one).</p>

<p>Example usages:</p>

<ol>
<li><p>source closed + API licenced</p></li>
<li><p>open source + API licenced</p></li>
</ol>

<p>I have found following examples of API licensing:</p>

<ul>
<li><a href="https://developers.google.com/maps/licensing" rel="nofollow">Google Maps API Licence</a></li>
<li><a href="http://www.mapillary.com/developer.html" rel="nofollow">Mapillary API</a></li>
</ul>

<p>To use an API over a network connection (as opposed to, e.g., the Windows API), a user communicates a request to the API host, or server, and awaits a response.  The host of the remote API can refuse to serve requests from users for probably any reason.</p>

<p>Such services often require users to accept a license as a condition of using the service, and they may charge a fee as a condition of the license.</p>

<p>A license to use a service is obviously not necessarily bound to a license for the use of its source code, just as the ability to reach the service is not dependent on the ability to see (let alone use) the code in any format, whether it be the source code or some compiled form of the code.</p>

<p>In essence, source licenses and service licenses have different primary goals, at least inasmuch as the source license seeks to restrict someone who has actual physical access to compiled code, and possibly source code.  Service licenses do not have that concern, though I have seen service licenses that also prohibit decompiling.  This is probably the result of a CYA attitude among lawyers: the language is already in the standard software license text, and it doesn't hurt anything to leave it in, and it <em>could</em> help if a service user somehow managed to download the program code.</p>

licensing software