Is creating a simulator/mock of an API considered &quot;derivative work&quot;?
<p>We have a number of clients integrating their software with a specific third party service via a HTTP REST API. In order for our clients to be able to test efficiently their software we need to create simulators (API mocks) of that HTTP service. The third party service has a requirement that we should not &quot;modify or create derivative works of Technology (incl the HTTP API)&quot;.</p>
<blockquote>
<p>Client's Production Environments:</p>
<ul>
<li>Client's Software Users -&gt; Client's Application -&gt; Third Party API</li>
</ul>
<p>Client's Test Environments:</p>
<ul>
<li>Client's Software Testers -&gt; Client's Application -&gt; Third Party API Mock/Simulator provided by us</li>
</ul>
</blockquote>
<p>We are building the mocks/simulators for that specific third party API, but they are solely based on our mocking/simulation opensource technology and not on the third party's server or API technology. The common thing between our simulators/mocks we crate and the real third party API is the definition of the service - the &quot;protocol&quot;, syntax and semantics of the HTTP messages.</p>
<p>Is creating a mock or a simulator of an API on top of our opensource technology for the purpose of testing software for our clients considered &quot;derivative work&quot;?</p>

<h2>No</h2>
<p>The copyright is in the code that takes the input and returns the output. You are not copying this.</p>
<p>Just like you can write an original calculator app that returns “4” when presented with “2+2”.</p>

software open-source-software derivative-work