Django: How to override unique_together error message?

Update 2016/10/20: See jifeng-yin's even nicer answer below for Django >= 1.7

The nicest way to override these error messages might be to override the unique_error_message method on your model. Django calls this method to get the error message whenever it encounters a uniqueness issue during validation.

You can just handle the specific case you want and let all other cases be handled by Django as usual:

def unique_error_message(self, model_class, unique_check):
    if model_class == type(self) and unique_check == ('field1', 'field2'):
        return 'My custom error message'
    else:
        return super(Project, self).unique_error_message(model_class, unique_check)

You can do this since Django 1.7

from django.forms import ModelForm
from django.core.exceptions import NON_FIELD_ERRORS

class ArticleForm(ModelForm):
    class Meta:
        error_messages = {
            NON_FIELD_ERRORS: {
                'unique_together': "%(model_name)s's %(field_labels)s are not unique.",
            }
        }

For DRF serializers you can use this

from rest_framework import serializers


class SomeSerializer(serializers.ModelSerializer):


    class Meta:
        model = Some
        validators = [
            serializers.UniqueTogetherValidator(
                queryset=model.objects.all(),
                fields=('field1', 'field2'),
                message="Some custom message."
            )
        ]

Here is the original source.