Every affiliate partner has one Partner ID and one or more Affiliate ID's (AID). An AID is a unique number tracking your bookings and commission. Every booking made on a Booking.com page that has your AID included in the URL, is allocated to your account.
You can find all your AID's that are not connected to a Product created in the Partner Center under 'Your Account > Other Affiliates' and all AID's connected to a specific Product under 'Performance > Product Performance'.
Your AID will always start with a ‘1’, ‘3’, ‘8’ or’ 9’ and is automatically added to all the products created in the Partner Centre.
An example of a link with an AID correctly added:
Please make sure that your AID is always in the URL, to avoid losing commission. This is the only way for us to track your affiliate reservations.