"This Is a Development Server" Flask Warning — What It Means and How to Fix It

Flask’s app.run() starts a development-only server that is fine for local testing but not for production.

For real traffic, you should use a production WSGI server such as Waitress or Gunicorn.

Using the dev server in production can hurt handling of concurrency, health checks, and malformed requests.

The Flask warning is a reminder to switch to a safer, more reliable deployment setup.