Everything in the atlas

The page and the [abap2UI5](artifact:abap2ui5-abap2ui5) service have to share an origin: an `endpoint` that resolves to another origin is refused, and abap2UI5 rejects a POST whose `Origin` names another host. A host that routes by the URL hash, such as a Fiori elements app or an app with a UI5 router, needs abap2UI5 1.146.0 or later, because 1.145.0 clears the host's hash after every roundtrip. One frontend per page: the first control that starts decides which endpoint the frontend comes from.