An apparatus with a subscription and notification service , the apparatus comprising: a processor; and a memory coupled with the processor, the memory comprising executable instructions that when executed by the processor cause the processor to effectuate operations comprising: obtaining a first subscription request to receive an event notification of a first resource by a subscriber device ; recording the requested first subscription in a second resource on the apparatus; based on an event condition obtained from the first subscription request being satisfied, transmitting a notification message associated with the event condition to the subscriber device, and recording the notification message associated with the event condition to a third resource on the apparatus, receiving a notification request to retrieve any missing recorded notification messages; and based on the notification request, sending a response, wherein the response comprises the missing notification messages, wherein the first subscription request comprises instructions to record notifications if a certain number of notification targets have failed to receive the notifications. a processor; and a memory coupled with the processor, the memory comprising executable instructions that when executed by the processor cause the processor to effectuate operations comprising: obtaining a first subscription request to receive an event notification of a first resource by a subscriber device ; recording the requested first subscription in a second resource on the apparatus; based on an event condition obtained from the first subscription request being satisfied, transmitting a notification message associated with the event condition to the subscriber device, and recording the notification message associated with the event condition to a third resource on the apparatus, receiving a notification request to retrieve any missing recorded notification messages; and based on the notification request, sending a response, wherein the response comprises the missing notification messages, wherein the first subscription request comprises instructions to record notifications if a certain number of notification targets have failed to receive the notifications. obtaining a first subscription request to receive an event notification of a first resource by a subscriber device ; recording the requested first subscription in a second resource on the apparatus; based on an event condition obtained from the first subscription request being satisfied, transmitting a notification message associated with the event condition to the subscriber device, and recording the notification message associated with the event condition to a third resource on the apparatus, transmitting a notification message associated with the event condition to the subscriber device, and recording the notification message associated with the event condition to a third resource on the apparatus, receiving a notification request to retrieve any missing recorded notification messages; and based on the notification request, sending a response, wherein the response comprises the missing notification messages, wherein the first subscription request comprises instructions to record notifications if a certain number of notification targets have failed to receive the notifications. <EOS>