No. The bundled server is a development server. It's not designed with production environments in mind.
It will not handle more than one request at a time by default.
If you leave debug mode on and an error pops up, it opens up a shell that allows for arbitrary code to be executed on your server (think os.system('rm -rf /')).
The development server doesn't scale well.
Flask uses Werkzeug's development server, and the documentation says the same thing:
The development server is not intended to be used on production systems. It was designed especially for development purposes and performs poorly under high load. For deployment setups have a look at the Application Deployment pages.
Deploying your application is as simple as installing a WSGI server like uWSGI or gunicorn and running that instead of Flask's development server:
gunicorn -w 4 -b 127.0.0.1:4000 myproject:app
If you are serving any static assets like images or videos, need low-level caching, or have higher concurrency demands, it's recommended to use a webserver like nginx and have it handle all of your requests.
In crappy ASCII form:
+----------+
| Client 2 |
+----------+
|
V
+----------+ +-------+ +----------+
| Client 1 |----->| nginx |<-----| Client 3 |
+----------+ +-------+ +----------+
^
|
V
/--------------------\
| useful nginx stuff |
| like asset serving |
| and rate limiting |
\--------------------/
|
V
+-------------+
| WSGI server |
+-------------+
To actually run the WSGI server process, you can use Supervisor. It automatically restarts the server if it fails for some reason, keeps logs, and runs as a daemon so your service starts when the server boots.
While lightweight and easy to use, Flask’s built-in server is not suitable for production as it doesn’t scale well and by default serves only one request at a time.
http://flask.pocoo.org/docs/0.12/deploying/