Is it permissible to work for a website that sells digital products, such as wholesale subscriptions, by purchasing the product from the website after the customer pays?

Digital products are either sold or leased. If ownership transfers to the buyer, it is a sale. If ownership remains with the seller and the buyer is granted usufruct for a specified period, it is a lease. Selling a described item in advance (Mawsoof fi al-Dhimmah) is not permissible except as a salam (forward sale), which requires full payment of the price at the time of the contract. However, leasing described usufructs in advance (Manfa'ah Mawsoofah fi al-Dhimmah) is permissible, and it is not a condition to pay the rent in advance at the time of the contract.