This django-registration backend implements a signup flow initially requiring
only a single field: an email address.

The backend creates a User with an unusable password. The username is
provided by a customizable generation function. The user is sent an
email with a link to create a username and password. Meanwhile, the
user is logged in and can start using the site.

There are two variations of the flow: one which requires both a username
and password when completing registration, and one which requires only
a password, leaving the autogenerated username in place.

Installation

pip install django-registration-email-only
add "registration_email_only" to INSTALLED_APPS list in your Django settings
add signup view to urls.py
create initial regsitration and registration completion page templates

Optional:

SetTestCookie middleware

Django normally requires that a user visit the signup or login page before
submitting the signup or login form. Enable this middleware to allow signups
and logins from any page on the site.