title: Why should vlucas/phpdotenv not be used on production environments?
body: <p>I am using Drupal 8 and I can see that there is already the vlucas/phpdotenv library in the vendor folder in my project.</p>
  
  <p>So I thought about using it and hence was going through the Github page of the library:<a href="https://github.com/vlucas/phpdotenv" rel="nofollow noreferrer">doetnv library</a></p>
  
  <p>The following is a part of the documentation:-</p>
  
  <blockquote>
    <p>phpdotenv is made for development environments, and generally should not be used in production. In production, the actual environment variables should be set so that there is no overhead of loading the .env file on each request. This can be achieved via an automated deployment process with tools like Vagrant, chef, or Puppet, or can be set manually with cloud hosts like Pagodabox and Heroku.</p>
  </blockquote>
  
  <p>My questions are:</p>
  
  <ol>
  <li>If it can be used in dev environment, what is the problem with using it in production environment?</li>
  <li>How can the automated deployment tools mentioned be used to load the environment variables?</li>
  </ol>