I have an application that will use flask and mongodb; I will probably host it on rackspace.
I need to understand how flask authenticating works. I have not found mu
I don't think that flask has any authentication built-in, only support for tracking sessions.
Here are some snippets for basic HTTP authentication and authentication with some third-party providers. Otherwise you will need to roll your own or use a framework that has this baked in (like Django)
Here is a discussion thread on this topic with a useful link