MudLink is a new protocol designed to be compatible with existing and upcoming networking APIs for the Web. These APIs, for security reasons, do not allow applications to speak just any protocol, but instead use a simple NUL-terminated message protocol. MudLink is designed to work with such systems.

MudLink messages are comprised of a single ASCII character denoting the type of message, followed by an optional string of text in UTF-8 encoding. The meaning of the text is defined by each type of message.

The two most important messages are the " message and the = message. The " message is sent by the server to the client to display text. The = message is sent from the client to the server when a user enters a command. A completely functional MudLink server needs only support the sending of " messages and the receipt of = messages.

Another very common message that most servers should use is the P message. This message sets the current command prompt displayed to the user.

Likely to be another popular message is the c message, which sets the drawing color for future " messages.