Warning: Altis v13 is no longer supported.

Mutagen File Sharing

Mutagen is a powerful tool for optimising file system mounts among other things (not just for Docker!).

Local Server provides an experimental integration with Mutagen to improve the performance of your development environment. This is unlikely to provide much benefit if you use Linux as your operating system.


To get started you will need to install the Mutagen Compose Beta. The beta version has integrated docker compose orchestration support through the mutagen-compose command.

In order to work you must be using Docker Compose v2, it is recommended to update Docker Desktop or Docker Engine to the latest version to get this.


The easiest way to install Mutagen on Mac is using HomeBrew.

brew install mutagen-io/mutagen/mutagen-beta mutagen-io/mutagen/mutagen-compose-beta

For all available builds see the releases page for the latest release and open the assets section.

If using the download directly open the zipped file and copy the mutagen-compose file to your /usr/local/bin directory. The mutagen-compose command should now be available in your terminal.

Other OSes

For all other available binaries including Windows see the releases page for the latest release and open the assets section.

For Windows once downloaded unzip file and move mutagen-compose.exe to somewhere referenced in your $PATH environment variable.

Although not recommended for Linux you may wish to use Mutagen with WSL, in which case you can use the appropriate Linux binary:

  • 386 for 32-Bit systems
  • AMD64 for 64-Bit systems
  • ARM or ARM64 for ARM systems

Activating Mutagen

Once installed you can set Mutagen up by running:

composer server start --mutagen

After installing Mutagen and running composer server start --mutagen for the first time, the Mutagen container will be built and Mutagen will perform an initial synchronization. This may take several minutes depending on the size of your project.

If you find that there are issues or problems with using Mutagen you can deactivate it by running the start command again without the --mutagen flag.

Configuring Shared Files

Mutagen not only improves file read times but also allows you to optimise which files are shared between your host machine and the Docker containers.

If you have no need for huge node_modules directories for example to be shared with the containers you can specify it in an array in your Altis composer.json config like so:

	"extra": {
		"altis": {
			"modules": {
				"local-server": {
					"ignore-paths": [

The same file patterns available in .gitignore files can be used, so *, ** and ! operators are all valid.