What is the ruling on buying gold online and keeping it in the company's vault, then selling it to them, knowing that I will not take possession of it hand-to-hand?

The fundamental condition for selling gold for cash is actual hand-to-hand possession (قبض حقيقي), or what takes its place, such as constructive possession (قبض حكمي) at the time of the contract. The possession of gold or cash by an agent, or its placement in a private vault with a brokerage firm, with the possibility of disposal and physical possession, is considered sufficient. It is not permissible for a gold sale contract to be contingent upon a future event or deferred to a future time. The option clause (خيار الشرط) is not valid in such contracts, nor are contracts where both countervalues are delayed, such as deferred sales. For the sale of gold bars for cash, it is a condition that both countervalues be taken possession of at the time of the contract. The buyer's possession of the bar is achieved by actually taking possession of the item itself, or through his agent, or by constructive possession through the designation of the bar and enabling the buyer to dispose of it, or by possessing a certificate that represents ownership of a specific and distinguishable bar, issued by reputable entities, and which grants the buyer the right to physically take possession of the bar whenever he wishes. The fulfillment of these regulations should be considered when dealing with gold through electronic platforms.