Signals are one of Django’s most powerful, yet often misunderstood, features. They help developers decouple application logic — allowing one part of the system to respond to events triggered elsewhere. But as I’ve seen in production-grade systems, traditional signals can become fragile, blocking, and unreliable under real workloads.

In this post, we’ll revisit Django signals from the ground up — what they are, why we use them, and how Django 6.0 now makes them more reliable than ever with background task integration. We’ll explore a modern implementation pattern that guarantees atomicity, durability, and at-least-once delivery of signal handlers.

Before we dive in, I recommend checking out my earlier article — Exploring Django 6.0 New Features: A Practical Landing Page with Template Partials, CSP, and Background Tasks. In that piece, I demonstrated Django 6.0’s new built-in background tasks by building a real-world PDF lead magnet landing page. The same background task mechanism will power the reliable signals approach in this post.