The linked document contains a technical summary of the APIs available in the GTR Beta release of March 2013. More APIs will be added and the functioning of existing APIs will change over time – readers are asked to check the GtR web portal to ensure they are working from the most current version.
At the time of writing, the GtR project provided two APIs: GtRAPI and CERIF. Both produce outputs in XML and JSON formats. The GtRAPI is the same API that is used by the web portal and there is a direct correlation between the visible information on the web portal screens and the output from the API. The CERIF API produces XML output using the CERIF schema, provides access to all the data currently held in the GtR Database and is stored in a highly structured format. Although JSON output for the CERIF API is available we would advise people to only use the XML interface.
More details in the document.