OpenSea which is currently the most popular NFT marketplace will be expanding its ecosystem and launching a brand new NFT marketplace named Seaport.
OpenSea made the announcement on May 20th that they will be releasing a new Web3 NFT marketplace (SeaPort) for trading of popular token collections. SeaPort will be a decentralized protocol that will be open to all content creators, developers and NFT collectors. SeaPort will provide a new way of trading NFTs which allows an arena for a buyer and seller to create there own deal or sale.
How is the SeaPort NFT marketplace different from OpenSea
Most current NFT marketplaces only provide a means for listings where one party agrees to supply an NFT (a seller) and the other agrees to supply a crypto payment (the buyer). Seaport takes a different approach: “offerers” can agree to supply a number of ETH / ERC20 / ERC721 / ERC1155 items, this is called the “offer.” In order for that offer to be accepted, a number of items must be received by the recipients indicated by the offerer — this is the “consideration.”
Every Seaport listing consists of the same structure, including an improved EIP-712 signature payload that clearly outlines what can be spent and what will be received back by whom. However, there are a number of different ways that the fulfiller can choose to have listings fulfilled.
The most straightforward fulfillment option involves choosing a specific listing and creating an implied “mirror” of that listing, where the fulfiller receives all offer items and supplies all consideration items. Seaport also supports the option to fulfill any number of listings at once through a set of “fulfillments” — each fulfillment corresponds to a single item transfer and indicates a group of offer items that the submitter can match with corresponding consideration items. As long as each consideration item on each listing is fully credited after all fulfillments have been applied, the offerer’s can leverage their coincidence of wants and complete their transfers. This enables elimination of redundant transfers (which are generally the most gas-intensive component of the protocol) and allows for novel and efficient transactions.
Offerers may also optionally elect to designate both a “zone” and a “conduit” on any listing. Anyone can create new zones or deploy new conduits. A zone is an account (usually a contract) that performs additional validation prior to fulfillment, and that can cancel the listing on behalf of the offerer.
A conduit is a contract where offerer’s set token approvals. The owner of the conduit can add and remove “channels” for the conduit, and registered channels can instruct the conduit on how to transfer tokens. These two concepts enable extensibility and upgradeability in a fully “opt-in” fashion, giving creators, collectors, and platforms additional ability to make their own choices regarding how they utilize Seaport while maintaining broad composability with other listings on the protocol.
Additionally, any listing can also opt to support partial fills of offered items, where fulfillers can elect to spend some portion of each of the total offered items and receive back an equivalent portion of each consideration item as long as the relative ratios remain unchanged based on the initial offer. Offerer’s can combine partial fills with criteria-based items to create standing offers to buy or sell multiple NFTs that all share a given characteristic.

Finally, the Seaport protocol supports “tipping” — a fulfiller may include additional consideration items when fulfilling a listing as long as they do not “tip” more than the original offer.
OpenSea announced that SeaPort is fully decentralized as well as open source stating “OpenSea does not control or operate the Seaport protocol — we will be just one, among many, building on top of this shared protocol.” They also stated the new platform eliminates redundant transfers, which can cause of high gas prices.