Gleam OTP

GitHub release Discord chat CI

A Gleam library for building fault tolerant multi-core programs using the actor model. It is compatible with Erlang’s OTP framework.

This library is experimental and will likely have many breaking changes in the future!

Gleam’s actor system is built with a few primary goals:


Add this library to your Gleam project.

gleam add gleam_otp

How to understand the Gleam OTP library

  1. Read the rest of this README.
  2. Understand Erlang’s OTP library.
  3. this blog post is a decent jumping off point.
  4. Gleam OTP test suite demonstrates what the library offers in more detail.

Actor hierarchy

This library defines several different types of actor that can be used in Gleam programs.

      ↙    ↘
   Actor   Task


The process is the lowest level building block of OTP, all other actors are built on top of processes either directly or indirectly. Typically this abstraction would be not be used very often in Gleam applications, favour other actor types that provide more functionality.


The actor is the most commonly used process type in Gleam and serves as a good building block for other abstractions. Like Erlang’s gen_server it will automatically handle OTP’s debug system messages for you.


A task is a kind of process that performs a single task and then shuts down. Commonly tasks are used to convert sequential code into concurrent code by performing computation in another process.


Supervisors is a process that starts and then supervises a group of processes, restarting them if they crash. Supervisors can start other supervisors, resulting in a hierarchical process structure called a supervision tree, providing fault tolerance to a Gleam application.

Limitations and known issues

This library is experimental there are some limitations that not yet been resolved.

Search Document