- Three good choices for hosting Flask apps are AWS EC2, Heroku and Digital Ocean.
- The basic deployment stack for a Flask application consists of the app, an application runner like Gunicorn and a reverse proxy like Nginx.
- Gunicorn should sit behind Nginx and listen on 127.0.0.1 (internal requests) not 0.0.0.0 (external requests).
- Use Werkzeug's ProxyFix to handle the appropriate proxy headers in your Flask application.