Masking layers in AGOL

[JocelynTutak]

Is layer masking available in AGOL? I'm building a map for use in a Story Map, and I'd like to mask a few of the layers by another polygon layer in the map. In Pro I'd use layer masking via the masking drop down menu (by clicking on the layer to be masked in the contents pane. It's on the Feature Layer super tab, on the Appearance tab, in the Drawing group). Is there any way to do something similar online, or do I need to create clipped versions of the layers I want to mask?

[BernSzukalski]

The list of apps I describe above are the JS API 4.x ones and will all support the new blending, effects, etc. A widely used app builder that is not JS API 4.x is Web AppBuilder. If you are using WAB, or if your organization has created custom app templates with WAB, those will not support the new capabilities.