What is the ruling on selling goods online without actually possessing them, relying on purchasing them from another seller after the customer pays for them and requests direct shipment to them? Is this considered a form of Salam (forward selling)? And is it permissible to contract with the original seller to remove the transaction from the realm of unlawfulness?

It is not permissible to sell specific goods before possessing them, due to the Prophet's (peace be upon him) prohibition of selling what you do not own. An exception to this is Salam (forward) sale, which is an agreement on an item described in terms of its characteristics, to be delivered at a specified future date in exchange for a price received at the time of the contract. Among the conditions for a Salam sale are that the capital (price) must be handed over to the seller at the time of the contract, and the item to be delivered (Muslam Fih) must be precisely describable.

Accordingly, it is permissible to display samples of goods and sell them through a Salam sale with these conditions. It is also permissible to display products without concluding a sales contract. If a person requests an item and promises to buy it without obligation, it is permissible for the seller to purchase it and then sell it to him, or for the seller to act as an agent for the owners of the goods or for the buyer in exchange for a commission.