orderref is the unique identifier for the order. This is your order reference number and is used by Feefo to uniquely identify an order. Each order will have this information so if the customer has bought a single item, the order reference will be used once. If the customer has bought five items as part of the same order, five items will have the same order reference. Feefo recognises where this relationship occurs and only sends a single feedback request email to customers purchasing multiple items.
orderref is also output as part of the data sent to your website through the reviews API using your API key. For more details, see Reviews API (Customisable Integration).