The BEAM VM is the runtime for Elixir, providing features like lightweight processes, garbage collection, and fault tolerance, which are essential for building concurrent applications.

The BEAM (Bogdan/Björn's Erlang Abstract Machine) virtual machine is the runtime environment that powers Elixir and provides it with a robust set of features designed for building scalable and fault-tolerant applications. One of the standout features of the BEAM is its ability to manage lightweight processes, allowing thousands of concurrent processes to run simultaneously with minimal overhead. Each process has its own memory and is isolated, meaning that if one process crashes, it does not affect others. This isolation is key to Elixir's fault tolerance philosophy, where systems are designed to recover gracefully from errors. The BEAM also employs efficient garbage collection, ensuring that memory is managed effectively without introducing significant performance bottlenecks. Additionally, the VM supports distribution, enabling Elixir applications to run across multiple nodes seamlessly. This makes it particularly well-suited for applications requiring high availability, such as web servers and real-time systems. Overall, the BEAM is integral to Elixir's design, allowing developers to harness its capabilities to build resilient and scalable applications.