Django Signals: Automate Reactions to Events

By NSLTD | Published on June 25, 2025

Django

Connect Events to Logic with Django Signals

Signals in Django allow decoupled components to communicate and react to events, such as saving a model or creating a user.

Why Use Signals?

• Trigger actions automatically when certain events occur
• Keep your code modular and clean
• Avoid logic duplication across views or serializers

Basic Example: Welcome Email on User Creation

from django.db.models.signals import post_save
from django.contrib.auth.models import User
from django.dispatch import receiver

@receiver(post_save, sender=User)
def send_welcome_email(sender, instance, created, **kwargs):
    if created:
        print(f"Welcome email sent to {instance.email}")

Common Signals

• pre_save / post_save
• pre_delete / post_delete
• m2m_changed
• Custom signals for your own app logic

Signals are perfect for background triggers—logging events, sending notifications, updating related models, and more.

“Let the app listen. Let the signal speak.”