OpenSea

OpenSea is a non-fungible token (NFT) marketplace founded in 2017 by Devin Finzer and Alex Atallah in New York. It launched as an Ethereum-only platform and grew into the largest NFT marketplace by all-time trading volume, hosting collections such as CryptoPunks, Bored Ape Yacht Club, Pudgy Penguins, Azuki, Doodles, and thousands of independent artist drops. The company has raised funding from investors including a16z, Paradigm, and Coatue.

The platform supports multiple blockchains: Ethereum, Polygon, Solana, Base, Arbitrum, Optimism, Avalanche, Klaytn, and Zora. Users connect a self-custody wallet such as MetaMask, Coinbase Wallet, or any WalletConnect-compatible app to list, bid, buy, or sell NFTs. Listings can be set at a fixed price, a Dutch auction, or a timed auction, and trades settle directly between wallets without OpenSea taking custody of user funds.

In early 2025 OpenSea launched OS2, a rebranded experience under the tagline “exchange everything” that added token trading alongside NFTs and introduced a new fee structure. The platform charges a service fee per transaction, while creator royalties are optional rather than enforced. OpenSea also publishes guides on NFT minting, collecting, and gas fees, and exposes a public API used by analytics tools, wallets, and third-party galleries. Its user base spans collectors, artists, gaming projects, and brands, and the marketplace remains one of the most widely used venues for trading digital assets across multiple chains.