How to check the TEMPLATE_DEBUG flag in a django template?

Assuming you haven't set TEMPLATE_CONTEXT_PROCESSORS to some other value in settings.py, Django will automatically load the debug context preprocessor (as noted here). This means that you will have access to a variable called debug in your templates if settings.DEBUG is true and your local machine's IP address (which can simply be 127.0.0.1) is set in the variable settings.INTERNAL_IPS (which is described here). settings.INTERNAL_IPS is a tuple or list of IP addresses that Django should recognize as "internal".

If modifying INTERNAL_IPS is not possible/suitable, you can do this with a context processor:

in myapp/context_processors.py:

from django.conf import settingsdef debug(context):  return {'DEBUG': settings.DEBUG}

in settings.py:

TEMPLATE_CONTEXT_PROCESSORS = (    ...    'myapp.context_processors.debug',)

Then in my templates, simply:

 {% if DEBUG %} .header { background:#f00; } {% endif %}

Django 1.9+

settings.py:

INTERNAL_IPS = (    '127.0.0.1',)

Templates:

{% if debug %}

https://docs.djangoproject.com/en/dev/ref/settings/#internal-ips says:

A list of IP addresses, as strings, that:

• Allow the debug() context processor to add some variables to the template context.

The debug context processor is in the default settings.py.