title: Flask at first run: Do not use the development server in a production environment
body: <p>I installed the Flask plugin in PyCharm Community Edition and I just have this simple code in my flask app:</p>
  
  <pre><code>from flask import Flask
  app = Flask(__name__)
  
  @app.route('/')
  def index():
      return '&lt;h1&gt;Hello!&lt;/h1&gt;'
  
  if __name__ == "__main__":
      app.run(debug=True)
  </code></pre>
  
  <p>And I get this message:</p>
  
  <pre><code>WARNING: This is a development server. Do not use it in a production deployment.
  Use a production WSGI server instead
  
  * Restarting with stat
  * Debugger is active!
  * Debugger PIN: 123-456-789
  * Running on http://127.0.0.1:5000/
  </code></pre>
  
  <p>Why am I getting this error when I run Flask?</p>
  
  <hr>
  
  <p><sub>A previous version of the message read "Do not use the development server in a production environment."</sub></p>