The Mixed Reality Service (MRS) provides registration and discovery services binding the real world of geospatial coordinates to the virtual world of Universal Resource Identifiers (URIs). The MRS protocol consists of three commands: ‘add’ and ‘delete’, which allow additions and deletions to a mapping of geographical coordinates to URIs; plus ‘search’, which performs searches by geospatial coordinates, returning a list of matching mapped URIs. Potential uses of MRS include mixed reality applications, guidance for autonomous vehicles and drones, and vastly simplified delivery of nearly all location-based services. Simple modifications to MRS make it suitable for shared virtual worlds.