Best type of Authentication to use for a custom Rest API?
<p>We have to create a custom API written in PHP that will expose data to various stakeholders. These stakeholders will get access to functions like:</p>

<ul>
<li>getUserDetails($uid)</li>
<li>getUserProducts($uid)</li>
<li>getUserDevices($uid)</li>
</ul>

<p>(and possibly more later on...)</p>

<p>My problem is that I am trying to decide on the best way to authenticate users of the API. I thought OAuth would be the way to go, but after reading <a href="https://stackoverflow.com/questions/4201431/what-exactly-is-oauth-open-authorization">this</a>, I got the impression OAuth is only really used for things like logging in via Facebook or Gmail etc. </p>

<p>So my question is really this: What is the best type of authentication to use when creating a PHP API that external stakeholders can use? And is OAuth relevant in such a case?</p>