Craft 3: how to call methods in another plugin's service? In Craft 2, we used to be able to do so by doing:

craft()-&gt;plugin1-&gt;myMethod();


from Plugin 2's service for example.

Now in Craft 3, I couldn't figure out a way to do it.

Plugin1::$plugin-&gt;myService-&gt;myMethod();


seems to only work within the Plugin 1's code base.
Assuming Plugin1 is their main plugin class file name, you could do:
\fully\qualified\namespace\Plugin1::getInstance()-&gt;myService-&gt;myMethod();

In order for this to work:

Craft must be installed.
Plugin1 must be installed and enabled in Craft.
Composer autoloading has to be working so that it knows where to find Plugin1

If you're doing this from a custom module, then you'll need to listen for the EVENT_INIT event, because plugins get instantiated after modules.
i.e.
Craft::$app-&gt;on(Application::EVENT_INIT, function() {
    \fully\qualified\namespace\Plugin1::getInstance()-&gt;myService-&gt;myMethod();
});