OpenDOAR: Directory of Open Access Repositories
is a UK-based website that lists academic open access repositories
. It is searchable by locale, content, and other measures. The service does not require complete repository details and does not search repositories' metadata.
As of 2015, OpenDOAR and the UK-based Registry of Open Access Repositories
(ROAR) "are considered the two leading open access directories
worldwide. ROAR is the larger directory and allows direct submissions to the directory. OpenDOAR controls submission of materials and is dependent on the discretion of its staff. OpenDOAR requires open access of scholarly publications; whereas ROAR allows other types of materials to be included. ROAR allows filtering by country, type of repository, and sorting by repository name."