The Cainiao tracking number format typically consists of a combination of letters and numbers. While there isn't a standardized format, as Cainiao collaborates with various carriers, a common structure includes a series of letters followed by numbers and often ending with letters again. These tracking numbers are designed to be unique to each package. Depending on the carrier handling the shipment, they can vary in length and format. For the most accurate information on a particular package, refer to the tracking details provided by the seller or the shipping confirmation.