CORE harvests, maintains, enriches and makes available metadata and pdf full-text content from many Open Access repositories. This makes it a useful access point for those who would like to develop applications making use of this content.
To support these activities, CORE is providing a free API. The API is currently experimental and we are expecting a first stable release by the end of July 2012. The API functionality is now being heavily developed, so we cannot guarantee that it will not change and will provide accurate results.
The documentation is available here.
Apart from the CORE API, CORE also offers a SPARQL endpoint for Linked Open Data enthusiasts which can be used to discover semantically similar papers across repositories. The SPARQL endpoint is available here.