In one example, a method includes receiving, from a client application executing on a client device, a message transmission request including a number assigned to a recipient device. The message transmission request is added to an outbound queue based on determining the message transmission request is valid. The message request is caused to be transmitted to the recipient device based on the message transmission request being included in the outbound queue. Status information is obtained specifying a status of transmission of the message, the status information including an indication of successful transmission of the message. A record of the message transmission request responsive to the causing the transmission of the message is stored, the storing including storing the message and the indication of successful transmission of the message.