title: Add subdomain to localhost URL
body: <p>I am writing an web application that behaves differently depending on a url prefix. The format is something like:</p>
  
  <pre><code>   https://myprefix.mycompany.com
  </code></pre>
  
  <p>The web app behaves differently based on myprefix. My web app extract that part from the URL and act on that.</p>
  
  <p>However, when I test on my local, I use an localhost address:</p>
  
  <pre><code>   https://localhost:1234
  </code></pre>
  
  <p>I counldn't do something like:</p>
  
  <pre><code>   https://myprefix.localhost:1234
  </code></pre>
  
  <p>What is the best way for me to test this scenario?</p>
  
  <p>Many thanks</p>