Assalaamu alaykum. Is it permissible for me to order a good on a website and pay for it after the website delivers the good to me (cash on delivery), which may take 10-15 days from the day I order, or does this fall under selling a debt for a debt (I buy something in the future and the seller sells something in future)?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ʻalayhi wa sallam, is His slave and Messenger.

If this commodity is owned by the website or the website is an agent representing the owner, then there is no harm in buying it from the website and paying on its delivery. This is not considered selling a debt for a debt; rather, it is a sale of an identified absent commodity, and there is no harm in delaying receiving it. It is permissible to delay the payment in this case.

In his work Ar-Risaalah, the Maaliki scholar Ibn Abi Zayd Al-Qayrawaani said, “There is no objection to selling a commodity that is not present at the session of the contract if its description (quantity and quality) is exactly specified, and no cash payment may be based on a condition or stipulation.”

However, if the commodity is not owned by the website and it does not act as an agent for its owner and, rather, the transaction is to buy a defined commodity, then it is invalid to delay the payment of the price because this transaction is considered a Salam contract (sale with full payment in advance). It is impermissible to delay the payment in the Salam contract; rather, it must be paid in the session of the contract.

The way out of this (to render this transaction lawful) is not to conduct the sale contract and that only a promise of it is made. When the buyer receives the commodity and accepts it, then he may conduct the sale contract with the website and pay the price or else return the purchased commodity.

Allah knows best.