Elixir handles concurrency using lightweight processes managed by the Erlang VM. These processes are isolated and communicate via message passing, allowing developers to build highly concurrent applications without the complexity of traditional threading models.

Concurrency in Elixir is one of its standout features, and it is fundamentally different from how many other programming languages approach the issue. Elixir leverages the Erlang VM (BEAM), which was designed with concurrency in mind. In Elixir, concurrency is achieved through lightweight processes that can be spawned easily and run independently. Unlike threads in traditional programming models, Elixir processes are isolated, meaning each process has its own memory and state. This isolation is key to building robust applications, as it prevents shared state issues that can lead to race conditions and other concurrency-related bugs. Communication between processes in Elixir is done via message passing. When one process wants to send data to another, it simply sends a message, which the receiving process can handle at its own pace. This model allows for non-blocking operations, where processes can continue executing while waiting for messages, leading to highly responsive applications. Additionally, Elixir provides features like supervision trees, which allow developers to define how processes relate to one another and how they should recover from failures. This hierarchical organization of processes adds a layer of fault tolerance, as if one process fails, its supervisor can restart it without affecting the rest of the system. Overall, Elixir's approach to concurrency not only simplifies the development of concurrent applications but also enhances their reliability and maintainability.