• pip install -e git://github.com/Nim65s/django-YummyEmailOrUsernameInsensitiveAuth.git#egg=django-yeouia
• Add AUTHENTICATION_BACKENDS = ['yeouia.backends.YummyEmailOrUsernameInsensitiveAuth'] to your settings.py
• Enjoy

Tested for

• Python 2.7, 3.4, 3.5
• Django 1.7.11, 1.8.13, 1.9.6 and 1.10a1

May work otherwise, but you should run tests :P

Django's default auth username is not case insensitive. (See #2273 and #25617)

But… Who cares ?

This backend tries:

1. username, case sensitive
2. username, case insensitive
3. email, case insensitive

And follows #20760.