choucrifahed / sbt-elm

Scala Build Tool (SBT) plugin for the Elm programming language



sbt-elm is a Scala Build Tool (SBT) plugin that integrates Elm projects in Scala/Play projects. It uses and follows the conventions of sbt-web.


To use a stable release, add the following to the project/plugins.sbt of your project: If you are using Elm 0.18:

addSbtPlugin("io.finstack" % "sbt-elm" % "0.1.3")

If you are using Elm 0.19:

addSbtPlugin("io.finstack" % "sbt-elm" % "0.2.0")

To use the latest from Github, add the following to the project/plugins.sbt of your project:

lazy val root =".")).dependsOn(sbtElm)
lazy val sbtElm = uri("")


  • Put your Elm files (with extension elm into src/main/assets/elm)
  • Run the elmMake task
  • Result is in target/web/public/main/js

Or in a Play Framework project:

  • Put your Elm files (with extension elm into app/assets/elm)
  • Run Play
  • Observe the JS file on http://localhost:9000/assets/elmMain.js

There are other tasks available:

  • elmReactor task allows you to run Elm Reactor from SBT.
  • elmRepl task will run the Elm interpreter, with your sources loaded.

However, Elm Package is not yet available from SBT to install packages, bump versions or publish your packages.

Multimodule Play project

Unfortunately, the current version of the plugin does not support multiple Play sub-modules. Therefore you can only have SbtElm enabled for a single module (see #2 for more details). The example below shows how to do this:

// in project/plugins.sbt: addSbtPlugin("io.finstack" % "sbt-elm" % "x.y.z")

// then in build.sbt

lazy val playModuleElm = project

lazy val playModule2 = project


Check the examples folder for example projects that use this plugin.

Adding arguments to elmMake

This setting for example enables the debugger (Elm 0.18+)

(ElmKeys.elmOptions in ElmKeys.elmMake in Assets) ++= Seq("--debug")

Hacking on the plugin

Run scripted to run the plugin test suite (which is barely existent at this point...)

Special Thanks

To the team behind sbt-purescript for heavily inspiring this plugin.