Hulde

When you build a concurrent system with Elixir, the real magic happens not only in the code that processes data, but also in the way you organize those processes. Supervisors, child specifications, the Registry, and dynamic supervision together give you a fault‑tolerant architecture where errors are contained, resources are cleaned up, and the whole system can be started or stopped reliably.

In this article we will walk through the essential concepts, illustrate each of them with fresh examples from a fictitious “smart‑home” domain, and explore the trade‑offs you may encounter when choosing restart strategies or temporary workers.

When you write Elixir code you quickly discover that the language is built on a runtime called the BEAM. One of the defining strengths of the BEAM is its ability to keep a system running even when parts of it fail. In this article we’ll explore the foundations of fault‑tolerance in Elixir, from the low‑level runtime errors that can crash a process to the high‑level supervision trees that automatically bring those processes back to life.

Why Fault‑Tolerance Matters

Imagine a web‑service that aggregates live sensor data from dozens of IoT devices. The service is