Learning Elixir: Module Attributes

I’ve published a new article in my Elixir learning series on dev.to exploring module attributes - the compile-time annotations and constants that describe and configure our modules.

The article covers:

• The three roles of module attributes: annotations, temporary storage, and compile-time constants
• Setting and reading attributes, and how compile time differs from runtime
• Using attributes as constants, including inside patterns and guards
• Precomputing values at compile time and exposing them through functions
• Documenting modules and functions with @moduledoc and @doc
• Describing function contracts with @spec and typespecs
• Defining custom types with @type, @typep, and @opaque
• The @vsn, @derive, @behaviour, and @impl attributes
• Registering custom attributes with Module.register_attribute/3 and accumulating values across the module
• Practical guidelines for when to reach for an attribute instead of a plain function

With complete working examples you can copy into IEx, you’ll learn how module attributes become the glue between documentation, configuration, and compile-time behavior - and how they shape the Elixir code you read every day.

Check it out: