[FIXED] Flask at first run: Do not use the development server in a production environment

Issue

I installed the Flask plugin in PyCharm Community Edition and I just have this simple code in my flask app:

from flask import Flask
app = Flask(__name__)

@app.route('/')
def index():
    return '<h1>Hello!</h1>'

if __name__ == "__main__":
    app.run(debug=True)

And I get this message:

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/

Why am I getting this error when I run Flask?

---

_{A previous version of the message read "Do not use the development server in a production environment."}

Solution

As of Flask 2.2, the development server always shows this warning. The development server is not intended for use in production. It is not designed to be particularly efficient, stable, or secure. Use a production WSGI server instead. See the deployment docs from Flask for more information.

That warning is just a warning though, it's not an error preventing your app from running. If your app isn't working, there's something else wrong with your code.

Answered By - davidism