The Global Multi-Resolution Topography (GMRT) synthesis is a multi-resolution compilation of edited multibeam sonar data collected by scientists and institutions worldwide, merged into a single continuously updated compilation of global elevation data. The synthesis began in 1992 as the Ridge Multibeam Synthesis (RMBS), was expanded to include multibeam bathymetry data from the Southern Ocean, and now includes other bathymetry from throughout the global and coastal oceans. In addition to our existing WMS service, we are developing a REST-like service for direct access to these gridded data in standard formats including GeoTIFF and GMT NetCDF. Additionally, we are developing an attribution metadata service for returning all relevant information about gridded data in an area, including cruises and compilations from which data was collected and the multibeam files used with direct links to the raw data. We will be publishing this as an XML service and also packaging this with the data itself in Bathymetry Attributed Grid (BAG) format.