NeXus is a joint effort of both the synchrotron and neutron scattering community to devlop a common data exchange format based on HDF. In order to simplify access to NeXus-files a NeXus-API is provided. This NeXus-API has been redesigned and expanded to cover both HDF versions 4 and 5. Only small changes to the API were necessary in order to accomplish. A new NeXus-API for IDL based on IDL C interface has been implemented.