BookingCenter supports a remote system sending a CRM Guest ID to the individual BookingCenter ‘Booking Engine’ or a Portal Booking Engine to requests.bookingcenter.com to pass off a CRM guest identifier and pick it up with the booking message when/if the booking was made from that CRM Guest.

BookingCenter supports this via a field called a 'CRM_GuestID' in the ‘Request Server API’ (available upon request to business partners) that passes the value generated by a remote CRM system via either a POST or GET command. Then the Central Reservation System adds a new field to the ‘Guest File’ that is picked up for each booking/modification/cancellation that occurs via an online booking, OTA, or GDS booking.

The RESNUM ('Booking ID')+ 'CRM_GuestID' syntax described in the Central Reservation System API allows ta business partners to track the CRM identifier to a booking/modification/cancellation event.