What is an NFT marketplace?

An NFT marketplace is a platform where people can list, browse, buy and sell NFTs. It works a bit like an online auction or classifieds site, except that ownership changes hands on a blockchain and buyers and sellers use crypto wallets. OpenSea is one of the best-known examples. If you are new to the tokens themselves, start with what is an NFT.

How do NFT marketplaces work?

To use a marketplace, you typically connect a crypto wallet that holds your NFTs and funds.

When you list an NFT or make an offer, the marketplace builds an order and asks you to sign it with your wallet. OpenSea's developer docs explain that every order on its site uses a protocol called Seaport. An order says what one side gives up, such as an NFT, and what it wants back, such as ETH or another token. When a buyer accepts, Seaport checks both sides and completes the swap in one transaction, so each party gets what the order promised.

This design means the marketplace mostly acts as a storefront and order book, while the smart contract does the actual exchange.

What fees do NFT marketplaces charge?

There are usually three kinds of cost:

• A marketplace fee, kept by the platform.
• A creator fee or royalty, paid to the artist or project.
• A gas fee, paid to the blockchain network, not the marketplace.

As an example, OpenSea's help center, as of May 2026, lists a 1% fee on NFT sales and a 10% fee on primary drop mints. It says sellers pay gas when listing for the first time or accepting an offer, and buyers pay gas when they purchase. Fees differ between marketplaces and can change, so the marketplace's own help pages are the place to check current rates. For more on network costs, see what are gas fees.

How do NFT royalties work, and are they enforced?

An NFT royalty, often called creator earnings, is a percentage of each resale meant to go to the original creator. A common Ethereum standard for this is ERC-2981. According to OpenZeppelin's documentation, ERC-2981 only signals who should get a royalty and how much. It does not force anyone to pay.

That is why royalties became a dispute. The Block reported in October 2022 that NFTs can be wrapped or moved with basic transfer functions, letting trades skip the royalty. Around that time, some marketplaces made royalties optional.

Today OpenSea's help center describes two types. With enforced creator earnings, the set percentage is paid at sale. With optional creator earnings, the creator suggests a percentage and the seller decides whether to pay it.