Wikipedia
VuFind (not to be confused with Vufind.com a computer vision and interest graph API company), is an open source library search engine that allows users to search and browse beyond the resources of a traditional Online public access catalog (OPAC). Developed by Villanova University, version 1.0 was released in July 2010 after two years in beta.
VuFind operates with a simple, Google-like interface and offers flexible keyword searching. While most commonly used for searching catalog records, VuFind can be extended to search other library resources including: locally cached journals, digital library items, and institutional repository and bibliography. The software is also modular and highly configurable, allowing implementers to choose system components to best fit their needs.
As of March 2016, a total of 126 institutions are running live instances of Vufind including the Georgia Tech Library, the London School of Economics, the National Library of Ireland, Yale University, and the DC Public Library.