The API provides a convenient point of access to information about biological pathways involving a specified physical entity (e.g. protein or small molecule) collected from public pathway databases. It gives machine-readable access to the same information browsed and searched by biologists and downloaded by computational biologists in BioPAX format for global analysis. Users can also download and install the cPath software to create a local mirror. All data is freely available, under the license terms of each contributing database.