The ARI Sync-Inventory (HTNG) is used to notifiy a booking source of the inventory amount available at a specific hotel property.

The ARI Sync -  Inventory (OTA) is used to notify a booking source of the inventory amount available at a specific hotel property.

The Hotel Availability Request message provides the ability to search single or multiple properties for detailed availability and pricing information. The request is flexible allowing for multiple ways to search for hotels, filter the rates returned and specify the response type.