Each message contains a built-in facility for supporting application-defined property values. These message properties allow you to implement application-defined message filtering.

Message properties are name-value pairs that you can optionally insert into messages to provide structure. For example, in the .NET API the pre-defined message property ias_Originator, identified by the constant MessageProperties.ORIGINATOR, provides the message store ID that sent the message. Message properties can be used in transmission rules to determine the suitability of a message for transmission.

There are two types of message property:

In either case, you access message store properties using get and set methods and pass the name of the pre-defined or custom property as the first parameter.

See Managing message properties.