The text describes how merchants can use the Nostr marketplace to sell their products to customers using NOSTR key-pairs. The marketplace software should be entirely clientside, either as a stand-alone app or as a purely frontend webpage. Customers subscribe to different merchant NOSTR public keys, and those merchants' stalls and products become listed and searchable. The marketplace client is like any other ecommerce site with basket and checkout. Marketplaces may also wish to include a customer support area for direct message communication with merchants.

Link: https://github.com/nostr-protocol/nips/blob/master/15.md