BiblioCommons is an innovative social discovery layer for public libraries, that combines powerful search and account management capabilities with a revolutionary social sharing and discovery platform. The BiblioCommons API provides unprecedented access to public library data, by leveraging the advanced search and discovery functionality provided for libraries by BiblioCommons. The API is meant to be used by library IT departments, tech-savvy library patrons, and 3rd party application developers who all share the common goal of extending the reach and impact of public libraries.