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Indigo is a game engine written in Scala for functional programmers. It allows game developers to build games using a set of purely functional APIs that are focused on productivity and testing.

Indigo is built entirely on Scala.js + WebGL, but it's sbt and Mill plugins will export games for web, desktop (via Electron), and mobile (via Cordova). Hypothetically consoles could also be supported.

Documentation can be found on

Thank you, to our sponsors! 💜

Thank you to all our wonderful sponsors, and particularly to dedipresta for their generous support.


If you'd like to help advance our work, we are ever grateful for all forms of contribution, either by volunteering time or financial backing.

Full local build and test instructions

Using Nix

The root of the project contains a very very simple flake.nix file that, if you have nix installed and flakes enabled, will give you all the tools you need to build Indigo by running nix develop in the root directory.

Build requirements

You will need:

  • Mill
  • SBT
  • JDK (Update: 8 works, 17 is used in Indigo's development)

Running the build

On Mac / Linux, from the repo root to do a full build and test:


On Windows, open up powershell and run:

& build.ps1

There is also another script which is a bit faster since it doesn't build the examples or demos.


Software requirements for running games

The list above covers the software needed to build Indigo itself, but to run a game you may also need:

  • NPM and/or Yarn
  • NodeJS
  • Electron
  • An http server that will serve static from a directory (suggestions: http-server via npm, or Python's SimpleHTTPServer)
  • A frontend packaging tool such as Parcel.js