The Fiqh of Self-Checkout Machines

The most vital components of a sale transaction are the Ījāb and Qabūl (offer and acceptance), as highlighted by Imam al-Qudūri (d.428 AH).ⁱ Imam al-Marghīnānī (d.593 AH) further emphasises that the essence lies in the Mʿanā (meaning) conveyed through the words used when making the offer and acceptance.ⁱⁱ According to the Fuqahā’, the core of a transaction and the definition of a Bayʿ (sale) is the exchange of goods between two parties, accompanied by an indication of mutual satisfaction.ⁱⁱⁱ

Satisfaction, however, is an internal matter that cannot be observed externally. Only the individual can confirm it. Therefore, a key principle is applied: any Amr bāṭin (internal matter) is judged based on an Amr dhāhir (external matter). In the case of a sale, the external matter typically manifests as the offer and acceptance, although this may not always be explicit.

For example, the Fuqahā’ discuss a type of transaction in their works known as Bayʿ al-Taʿāṭī, which occurs through the mere exchange of goods. In such cases, the seller hands over the goods, and the buyer provides the payment. The Fuqahā’ state that this is permissible because the offer and acceptance are simply tools to express the mutual satisfaction of both parties. The act of willingly exchanging goods and money is itself sufficient to demonstrate their consent and approval. ^iv

When purchasing from a shop, items displayed on shelves are not regarded as an Ījāb but rather as an invitation to treat. This principle is consistent with the opinion of Mufti Muhammed Taqi Uthmani as well as UK law. An invitation to treat refers to a pre-contractual communication that indicates a willingness to negotiate but does not constitute a legally binding offer. Instead, it invites the customer to make an offer, which the seller may then choose to accept. This means that if someone brings an item to the till, the shopkeeper is not legally obligated to sell it at the displayed price.^v

In regard to the self-checkout, the Ījāb occurs when a customer takes an item to the self-checkout and scans it. At this point, the displayed price represents the shop owner’s offer. The Qabūl (acceptance) happens when the customer makes the payment. If the payment is declined, Milkiyyah (ownership) of the item does not transfer. Consequently, approval of the payment is an essential part of the Qabūl.

A self-checkout machine can be understood as a modern form of Kitābah (written communication). Imam al-Marghīnānī explains that written words can be treated in the same way as spoken ones.^vi For instance, if someone writes, “I have sold x item to you for £x,” and the customer accepts upon reading this, the transaction becomes valid. This shows that verbalising the offer and acceptance is not critical; rather, what matters is that both parties are content and wish to proceed with the transaction.

The self-checkout serves as a contemporary form of Kitābah by conveying the prices of items the shop owner is willing to sell. The machine is programmed—either directly by the owner or by someone hired for the task—to communicate these prices. It uses an algorithm to respond to scanned items with their corresponding prices. In essence, this is equivalent to the owner writing to the customer, stating the price they are willing to accept for each item.

Hence, the self-checkout can be seen as a modern form of a transaction conducted through Kitābah. The total price displayed by the machine represents the amount at which the shop owner is willing to sell the item(s). When the customer selects ‘accept and pay’ and the payment is successfully processed, this constitutes the customer’s acceptance.