An e-mail processing system includes: a non-persistent or random memory storing a message queue map having a plurality of message queues, an input handler, and an output handler. Each message queue includes a plurality of data nodes, and each data node represents one message intended for delivery to a respective domain. The input handler comprises instructions for: (i) obtaining an incoming first e-mail, (ii) digesting the incoming first e-mail into a first data node representing the incoming first e-mail, and (iii) analyzing the first data node to determine a first message queue in the number of message queues based at least on the destination domain of the first data node, and (iv) appending the first data node to the plurality of data nodes in the first message queue. The output handler processes a data node in a message queue in the message queue map to send e-mail to an intended recipient.