Call context transfer from one call center system to other call center system(s)

Methods, systems, apparatuses, and computer-readable storage mediums described herein are configured to transfer call context between different call center systems. For example, a first call center system that establishes a communication session between a user and an agent of the first system provides context determined during the session to a call context service. The service stores the context and provides it to other requesting call center systems. For instance, during a call transfer to an agent of a second system, the first system requests the service to provide a transfer number of the second system to which the user is to be transferred. The service determines the transfer number and provides it to the first system. The first system performs the call transfer using the number. After the transfer is complete, the second system provides a request for the context, and the service provides the context to the second system.