Django override default form error messages

How can I overwrite the default form error messages (for example: need them in other language) for the all apps in my project (or at least for 1 app)

Thanks!

The easiest way is to provide your set of default errors to the form field definition. Form fields can take a named argument for it. For example:

my_default_errors = {
    'required': 'This field is required',
    'invalid': 'Enter a valid value'
}

class MyForm(forms.Form):
    some_field = forms.CharField(error_messages=my_default_errors)
    ....

Hope this helps.

To globally override the "required" error message, set the default_error_messages class attribute on Field:

# form error message override
from django.forms import Field
from django.utils.translation import ugettext_lazy
Field.default_error_messages = {
    'required': ugettext_lazy("This field is mandatory."),
}

This needs to happen before any fields are instantiated, e.g. by including it in settings.py.