Django admin – make all fields readonly

Since django 2.1, you can prevent editing, while allowing viewing, by returning False from the ModelAdmin‘s has_change_permission method, like this:

class CustomAdmin(admin.ModelAdmin):
    def has_change_permission(self, request, obj=None):
        return False

(This will not work before django 2.1, as it will also deny permission to any user trying only to view.)