title: What is the purpose of a build agent in continuous integration and continuous deployment?
body: <p>What is the purpose of a build agent in continuous integration (CI) and continuous deployment? Is this something that impacts all CI servers (e.g. Jenkins, TeamCity, TFS, etc.)</p>
  
  <p>On the TeamCity license types page I noted that the professional server license, which is free, only includes three build agents.</p>
  
  <p><a href="https://www.jetbrains.com/teamcity/buy/#license-type=new-license" rel="nofollow noreferrer">https://www.jetbrains.com/teamcity/buy/#license-type=new-license</a></p>