Miss. Code § 27-65-7
"Retailer" shall apply to a person making retail sales through vending machines, by maintaining a store, or operating as a transient vendor, or renting or leasing tangible personal property. Retailer also includes persons who facilitate the sale of services or tangible personal property that belongs to a third party.
"Retail sales" shall mean and include all sales of tangible personal property physically or electronically delivered or located within this state, except those defined herein as wholesale and those made to a wholesaler, jobber, manufacturer or custom processor for resale or for further processing.
"Retail sale" shall include the value of any tangible personal property manufactured or purchased at wholesale which is withdrawn from the business or stock in trade and is used or consumed within this state in the business or by the owner or by any other person, whether or not in the regular course of business or trade.
"Retail sale" shall also include a sale invoiced to a retailer but delivered to another person who pays for the merchandise upon taking possession.
"Retail sale" shall also include a sale made or facilitated by a person regularly engaged in the sale or facilitation of sales of services or tangible personal property. "Retail sale" does not include a sale by a third-party food delivery service that delivers food from an unrelated restaurant to a customer, regardless of whether the customer orders and pays for the food through the delivery service or whether the delivery service adds fees or upcharges to the price of the food.
Computer software maintained on a server located outside the state and accessible for use only via the internet is not a taxable retail sale.
Miss. Code § 27-65-7