title: What is the difference between Workers and Threads in Puma
body: <p>What is the difference between a puma worker and a puma thread in context of a heroku dyno?</p>
  
  <p>What I know (please correct me if I am wrong):</p>
  
  <ul>
  <li><p>Thin is not concurrent, so a web process can only do one request at a time</p></li>
  <li><p>In unicorn, I know I can have several unicorn workers in one process to add concurrency.</p></li>
  </ul>
  
  <p>But in puma there is threads and workers.. Isn't a worker a thread inside the puma process? </p>
  
  <p>Can I use more workers/threads to add web concurrency in Heroku?</p>