A messaging system facilitates communication between users through various messaging channels. The messaging system supports multiple communication channels and includes a messaging module that automatically selects one or more of the messaging channels for delivering a message to a recipient of the message using, for example, a set of policy rules or a trained model. The messaging module may also provide, in a user interface for sending and receiving messages, a visual indication of the selected messaging channel to the sender of the message to provide the user with transparency about how the message will be delivered. Additionally, the message may be delivered via multiple messaging channels, where the messaging module may rescind messages from some of the messaging channels upon receiving a reply from the recipient of the message or other confirmation that the recipient has seen the message via one of the communication channels.