Installing Sandbox Modules

In addition to the contrib modules which have been through the project review process, there are less rigorously vetted modules known as sandbox modules. These modules are not covered by the Drupal security check process and are not packaged for download. 

Sandbox modules tend not to be as widely used as contrib modules. They may be incomplete and may not have good support. On the other hand, some of them are quite good and merely need reviewers to get them through the project application review process.

Composer install of Sandbox modules

Sandbox modules with a composer.json

If the Sandbox module has a composer.json file that include "type": "drupal-module", you can add it as a vcs repository entry to your composer.json "repositories" array:

    "repositories": [
        {
            "type": "composer",
            "url": "https://packages.drupal.org/8"
        },
        {
            "type": "vcs",
            "url": "git@git.drupal.org:sandbox/username-12345678.git"
        }
    ],

Check the available versions with composer show (where drupal/foo is the package name defined in the Sandbox project's composer.json):

composer show drupal/foo --all

Then use composer require drupal/foo:1.0.x-dev to install the module (replace the version string).

Sandbox modules without a composer.json

It is still possible to use Composer to install Sandbox modules that don't have their own composer.json file, but you must add the repository to your own composer.json to be able to do this. This is an example showing how to install MegaChriz's Feeds Dev module:

add the following to the "repositories" section of your composer.json:

"drupal/feeds_dev": {
    "type": "package",
    "package": {
        "name": "drupal/feeds_dev",
        "type": "drupal-module",
        "version": "1.x-dev",
        "source": {
            "url": "git@git.drupal.org:sandbox/megachriz-2950698.git",
            "type": "git",
            "reference": "8.x-1.x"
        }
    }
}

and then on the command line:

composer require drupal/feeds_dev:1.x-dev

If you want to work on the module in an instance, you can add the --prefer-source switch and this will check out the repository.

composer require drupal/feeds_dev:1.x-dev --prefer-source