Notifications can optionally have a type indicator. Although neither client or nor server must support this, some may choose to. Those servers implementing notification types may use them to intelligently display the notification in a certain way, or group notifications of similar types.
The following table lists standard notifications as defined by this spec. More will be added in time.
Table 2. Notification Types
|"email"||An e-mail notification.|
|"im"||A new IM notification.|
|"device"||A device-related notification, such as a USB device being plugged in or unplugged.|
|"presence"||A presence change, such as a user going online or offline.|
|"transfer-complete"||A file transfer or download complete notification.|
Third parties, when defining their own notification types, should discuss the possibility of standardizing on the hint with other parties, preferably in a place such as the xdg mailing list at freedesktop.org. If it warrants a standard, it will be added to the table above. If no consensus is reached, the notification type should be in the form of "x-vendor-name."