Within the family of FHIR HL7 IGs this use case is covered.  The particular use you are describing is covered in Da Vinci PDEX with depends upon US Core.  Will add the following text to section 1.3 to clarify that the actors are not limited to those presented in the examples. The terms " US Core Requestor " and "Client"  are   used interchangeably throughout this guide and   we don’t mean to limit ourselves to only patient and provider apps, the same technology can be used by payers and other users. Please read “Client” here as a short-hand notation for something like “user application” The terms " US Core Responder" and "Server" and "EHR" are   used interchangeably throughout this guide and we don’t mean to limit ourselves to electronic health record systems.  The same technology can be used in HIEs, care coordination platforms, population health systems, etc. Please read "Server" or “EHR” as a short-hand notation for something like “interoperable healthcare platform”