California Digital Library EZID PHP SDK by Robert Olendorf is a simple wrapper around the Guzzle HTTP client intended to simplify interaction with the EZID DOI service. It is configurable to use your own authentication and shoulders. The recommended way to install California Digital Library EZID PHP is through Composer. Please note: the SDK is still in development.
For further information about the EZID API visit http://ezid.lib.purdue.edu/doc/apidoc.html.