To date many institutional repository (IR) software suppliers have pushed the IR as a digital preservation solution. We argue that the digital preservation of objects in IRs may better be achieved through the use of light-weight, add-on services. We present such a service – PRONOM-ROAR – that generates file format profiles for IRs. This demonstrates the potential of using third- party services to provide preservation expertise to IR managers by making use of existing machine interfaces to IRs.