Elixir boasts several key features, including immutable data structures, lightweight processes, fault tolerance, and a powerful macro system for metaprogramming. These features contribute to Elixir's suitability for building concurrent, scalable applications.

Elixir's key features make it a compelling choice for modern software development, especially for applications that require scalability and maintainability. One of the most notable features of Elixir is its emphasis on immutability. In Elixir, once a data structure is created, it cannot be altered. This leads to more predictable code and helps avoid common bugs related to mutable state. Another cornerstone of Elixir is its lightweight process model, which allows developers to spawn thousands of concurrent processes without significant performance penalties. Each process has its own state and memory, enabling fault isolation; if one process crashes, it doesn't affect others. This leads to enhanced fault tolerance, a hallmark of applications built on the Erlang VM. The ability to define supervision trees allows developers to implement robust recovery strategies for their applications, ensuring high availability. Elixir's macro system is also a powerful feature, enabling developers to extend the language itself by writing code that writes code. This allows for the creation of domain-specific languages and can lead to cleaner and more expressive code. Additionally, Elixir has a rich ecosystem of libraries and tools, such as the Mix build tool and the Phoenix web framework, which enhance productivity and streamline the development process. Together, these features make Elixir an excellent choice for developing scalable, fault-tolerant applications in various domains, from web services to embedded systems.