BASE (Bielefeld Academic Search Engine) is a multi-disciplinary search engine to scholarly internet resources, created by Bielefeld University Library in Bielefeld, Germany. It is based on search technology provided by Fast Search & Transfer (FAST), a Norwegian company. BASE is a registered service provider for the Open Archives Initiative (OAI). OAI metadata are "harvested" for the BASE project from scientific digital repositories that implement the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). In addition to OAI metadata, the library indexes selected web sites and local data collections, all of which can be searched via a single search interface.