Want to learn and master ReasonML?

Join Exercism’s ReasonML Track for access to 24 exercises with automatic analysis of your code and personal mentoring, all 100% free.

Explore exercises

About ReasonML

let message = () => "Welcome to Reason!";

Key Features of ReasonML


OCaml's type system

ReScript brings OCaml's battle-tested powerful type system to Javascript.

Inferred types

No need to specify types, types are inferred by ReScript compiler and are guaranteed to be correct.

Functional Programming

Like OCaml, ReScript is a functional programming language with pattern matching, variants and more.

Easy javascript interop

Javascript interop is easy allowing advatange of existing javascript packages and ecosystem.

Fast compiler

ReScript compilation times are super fast which means fast iteration cycles.

Refactor with ease

Compiler guides you through all places that need to be fixed during refactor until it just works.

Get mentored the ReasonML way

Every language has its own way of doing things. ReasonML is no different. Our mentors will help you learn to think like a ReasonML developer and how to write idiomatic code in ReasonML. Once you've solved an exercise, submit it to our volunteer team, and they'll give you hints, ideas, and feedback on how to make it feel more like what you'd normally see in ReasonML - they'll help you discover the things you don't know that you don't know.

Learn more about mentoring

Community-sourced ReasonML exercises

The ReasonML track on Exercism has 24 exercises to help you write better code. Discover new exercises as you progress and get engrossed in learning new concepts and improving the way you currently write.

See all ReasonML exercises

Get started with the ReasonML track

The best part, it’s 100% free for everyone.