Credo Reference or Credo is an American company that offers online reference content by subscription and partners with libraries to develop information-literacy programs or produce library marketing plans and materials. Founded in 1999, Credo Reference provides full-text online versions of over 3,500 published reference works from more than 100 publishers in a variety of major subjects. These include general and subject dictionaries as well as encyclopedias. The company's customers are libraries, library systems, k-12 schools, and universities, which subscribe to the service for their patrons' use.