Both XML namespaces and standoff annotation are promising approaches to tackle possibly overlapping multiple annotation layers in XML instances. The creation and processing of standoff instances can be cumbersome – especially when the underlying textual primary data is allowed to be modified after the annotation has been added. In this paper we present a powerful API that is capable of dealing with these tasks by providing an extension mechanism that allows for the easy creation of modules corresponding to a certain namespace (and therefore markup language). We use XStandoff as a working example since it is a standoff format that highly depends on XML namespaces for different annotation layers.