Does the Gleam compiler check types for Erlang FFI?

No, the compiler cannot verify that the external code matches your annotations. You must manually ensure type accuracy and write extensive unit tests to verify the integration.

How do I call Elixir functions from Gleam?

Use the @external attribute with the 'erlang' target and prefix the Elixir module name with 'Elixir.', for example: @external(erlang, "Elixir.String", "upcase").

How are Gleam custom types represented in Erlang?

Simple variants become atoms (e.g., Loading becomes 'loading'), while variants with fields become tagged tuples (e.g., LoggedIn(id) becomes {logged_in, Id}).

Can I use Elixir macros directly in Gleam?

No, Elixir macros cannot be called directly from Gleam. You must wrap the macro logic in a standard Elixir function and then call that function via FFI.

Gleam Erlang Interop

Name: Gleam Erlang Interop
Author: renatillas

byrenatillas

Developer Tools

Integrates Gleam with Erlang and Elixir ecosystems using Foreign Function Interface (FFI) and type-safe BEAM patterns.

About

This skill empowers developers to bridge the gap between Gleam and the broader BEAM ecosystem. It provides comprehensive guidance on using the @external attribute for FFI, mapping complex data types between languages, and integrating with Elixir modules or existing Erlang libraries. By emphasizing safety through mandatory type annotations and rigorous testing patterns, it helps maintain Gleam's robustness while leveraging the mature performance of OTP and the Erlang runtime.

Key Features

0 GitHub stars
Expert @external attribute syntax for Erlang and Elixir FFI
Best practices for safe API design around unsafe external calls
Guidance for Elixir module integration and macro wrapping
Support for OTP patterns and BEAM-specific performance optimizations
Precise data type mapping between Gleam and BEAM atoms/tuples

Use Cases

Calling existing Erlang libraries or Elixir modules within a Gleam project
Migrating existing Elixir or Erlang codebases to Gleam incrementally
Building high-concurrency systems using Gleam OTP and actor patterns

About

Key Features

0 GitHub stars
Expert @external attribute syntax for Erlang and Elixir FFI
Best practices for safe API design around unsafe external calls
Guidance for Elixir module integration and macro wrapping
Support for OTP patterns and BEAM-specific performance optimizations
Precise data type mapping between Gleam and BEAM atoms/tuples

Use Cases

Calling existing Erlang libraries or Elixir modules within a Gleam project
Migrating existing Elixir or Erlang codebases to Gleam incrementally
Building high-concurrency systems using Gleam OTP and actor patterns