Protocol to Initiate Session With Partner Site

A system comprising:

• at least one processor;
• and
• memory having stored thereon computer-readable instructions that are executable by the at least one processor to implement an application to provide combined service from multiple different service provider systems by performing operations including:
• collecting session information describing a context of requested functionality involving interaction between multiple service provider systems;
• obtaining storage allocated to the application by a service provider system providing the requested functionality, the allocated storage obtained by communicating with the service provider system providing the requested functionality using a non-personally identifying session identifier generated based on the session information;
• creating a hidden storage area local to the application using the allocated storage;
• storing at least some of the session information in the hidden storage area;
• and
• surfacing the requested functionality locally from the application based, in part, on the session information stored in the hidden storage area.

In a digital medium environment to reduce exposure of sensitive information in connection with providing combined services from multiple service provider systems, a method implemented by a computing device of a service provider system, the method comprising:

• receiving, from a client device, information describing a context of a request for functionality involving interaction with at least one other service provider system;
• initiating a partner session with the client device for provision of the requested functionality, said initiating including:
• generating an abstract session identifier based on the received information;
• communicating the abstract session identifier to the client device;
• and
• allocating storage to the client device based on the abstract session identifier, the allocated storage configured for creation of a hidden storage area local to an application of the client device, and the hidden storage area usable by the application for provision of the requested functionality locally from the application.