1. One or more non-transitory computer storage media storing computer executable instructions which when executed perform a method in a computer system for graphically defining a channel for processing messages, the method comprising: displaying, on a display device, a visual channel editor in which graphical representations of channel nodes can be arranged and interconnected to define a channel; receiving user input to the visual channel editor that creates a plurality of graphical representations of channel nodes in the visual channel editor, the plurality of graphical representations including a graphical representation of a source node and at least one graphical representation of a destination node; receiving user input that selects one of the graphical representations, the selected graphical representation corresponding to a first channel node; in response to the selection of the graphical representation, displaying, on the display device, a node configuration panel that displays one or more user interface controls that the user can manipulate to define configurable parameters for the first channel node, wherein the one or more user interface controls displayed in the node configuration panel include one or more fields that each list a number of predefined types for the first channel node that a user can select, and wherein the first channel node is a source node, and wherein the one or more fields include a source field and a format field, the source field for defining a source of messages to be processed in the channel, and the format field for defining a format for the messages; receiving user input to the one or more user interface controls, the user input defining configurable parameters for the first channel node; and using the user input to the one or more user interface controls to automatically generate one or more scripts to implement functionality specified in the defined configurable parameters on messages that are processed by the first channel node.