A system for operating a telecommunications network, the system comprising: an off-premises cloud computing system; and an on-premises computing system comprising at least one processor (208, 216, 224) configured for: executing one or more network-impacting telecommunications functions for the telecommunications network, wherein each of the network-impacting telecommunications functions is capable, in operation, of disrupting service on the telecommunications network such that a subscriber cannot make or receive calls or send and receive data, and each of the other telecommunications functions is not capable, in operation, of disrupting service on the telecommunications network; and offloading one or more other telecommunications functions for the telecommunications network to the off-premises cloud computing system, wherein offloading the other telecommunications functions for the telecommunications network to the off-premises cloud computing system comprises sending telecommunications data to the off-premises cloud computing system using a cloud application programming interface, API, for an application implementing one of the other telecommunications functions, characterized in that the off-premises cloud computing system is configured to execute an event recorder to record events generated by applications implementing the other telecommunications functions executing on the off-premises cloud computing system, and wherein the off-premises cloud computing system is configured to replay services after cloud services become available following an outage using events recorded prior to the outage. an off-premises cloud computing system; and an on-premises computing system comprising at least one processor (208, 216, 224) configured for: executing one or more network-impacting telecommunications functions for the telecommunications network, wherein each of the network-impacting telecommunications functions is capable, in operation, of disrupting service on the telecommunications network such that a subscriber cannot make or receive calls or send and receive data, and each of the other telecommunications functions is not capable, in operation, of disrupting service on the telecommunications network; and offloading one or more other telecommunications functions for the telecommunications network to the off-premises cloud computing system, wherein offloading the other telecommunications functions for the telecommunications network to the off-premises cloud computing system comprises sending telecommunications data to the off-premises cloud computing system using a cloud application programming interface, API, for an application implementing one of the other telecommunications functions, executing one or more network-impacting telecommunications functions for the telecommunications network, wherein each of the network-impacting telecommunications functions is capable, in operation, of disrupting service on the telecommunications network such that a subscriber cannot make or receive calls or send and receive data, and each of the other telecommunications functions is not capable, in operation, of disrupting service on the telecommunications network; and offloading one or more other telecommunications functions for the telecommunications network to the off-premises cloud computing system, wherein offloading the other telecommunications functions for the telecommunications network to the off-premises cloud computing system comprises sending telecommunications data to the off-premises cloud computing system using a cloud application programming interface, API, for an application implementing one of the other telecommunications functions, characterized in that the off-premises cloud computing system is configured to execute an event recorder to record events generated by applications implementing the other telecommunications functions executing on the off-premises cloud computing system, and wherein the off-premises cloud computing system is configured to replay services after cloud services become available following an outage using events recorded prior to the outage.