What is OpenSea?

OpenSea is your home for discovering and trading everything onchain. Founded in 2017, the platform pioneered the first non-custodial marketplace for digital assets and has since evolved into a one-stop portal to the entire onchain economy. Use OpenSea to find tokens, culture, ideas, and digital and physical items, and then seamlessly trade through your connected wallet.

What do I need to use OpenSea?

You’ll need a self-custodial crypto wallet (for example, an Ethereum-compatible wallet) and the native currency of the chain you’re using to cover network (“gas”) fees when required. OpenSea supports dozens of blockchains and is continually adding more.

How do self-custodial wallets work with OpenSea?

OpenSea is a dapp (decentralized application) that helps you interact with blockchain networks directly through your connected self-custodial wallet. When you choose actions like “Buy now,” “Make offer,” “List for sale,” or “Mint,” OpenSea formats your selections into blockchain-readable instructions and passes them locally to your connected wallet software. Your wallet presents those instructions for you to sign using your private key. If your action involves a transaction (like “Buy now”), your wallet broadcasts the transaction to the blockchain network for execution.

This model keeps your private keys in your wallet, not on OpenSea.

What happens when I take actions like “Buy now” or “Swap”?

1. OpenSea converts your selections (e.g., price, item, amount, offer or listing duration) into instructions that are compatible with the blockchain you’re interacting with.
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2. Through a local software handshake, OpenSea passes those coded instructions to your connected wallet software.
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3. Your wallet software checks the order, calculates gas, and prompts you to sign an order with your private key.
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4. Once you sign the order, your wallet broadcasts a transaction to the blockchain network for execution.
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5. A blockchain validator confirms that all order conditions are met and if so, executes the transaction by updating the state of the blockchain. 
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6. OpenSea updates to reflect that the transaction has been recorded to the blockchain.

That’s the wallet handshake at work: OpenSea passes instructions; you perform the transaction through your wallet.

Which blockchains and assets can I use?

OpenSea supports leading EVM chains so you can explore a broad range of assets with familiar wallet flows. Compatibility today includes Ethereum (L1) and popular L2s like Polygon, Arbitrum, and Optimism, plus select L1s like Solana and Avalanche. Each chain has different fees, speeds, and ecosystems; choose the one that fits your use case.

How do gas fees work?

“Gas” is the network fee paid to validators to include your transaction in a block. Gas rises and falls with network demand; OpenSea doesn’t set or receive gas fees. Your wallet will display an estimated gas fee before you confirm. Some actions (like signing an off-chain offer) may be gasless.

How are NFT listings, offers, and transactions powered?

NFT actions run on smart contracts, which are automated programs that execute actions that you’ve approved. OpenSea designed the Seaport smart contract protocol for security and flexibility. When OpenSea formats your actions into blockchain-compatible code, it utilizes the Seaport protocol for efficient and sophisticated transaction logic.

Listings and offers that you create using OpenSea are expressions of willingness or interest, configured as signed orders. They don’t execute on their own. A transaction occurs when another party reviews your listing or offer, signs a corresponding order in their own wallet, and submits the transaction to the blockchain for execution. OpenSea does not transmit your signed orders or transaction instructions to the blockchain.

Although OpenSea developed Seaport, it serves as a neutral, permissionless smart contract protocol that is used by numerous dapps.

Can I mint or create NFTs on OpenSea?

Yes. Using OpenSea Studio, you can mint NFTs and list the NFTs for sale. As with other actions, OpenSea will format the necessary transaction instructions and pass them to your wallet software. By signing those instructions in your wallet, you can deploy a new NFT collection smart contract, mint NFTs, and list those NFTs for sale.

How does OpenSea show real-time data and context?

For developers and AI apps, OpenSea’s Model Context Protocol (MCP) server exposes real-time NFT, wallet, and marketplace data across dozens of chains through a single connection, bringing richer context than raw chain feeds (e.g., collection verification, rarity, live listings/offers). This same data backbone helps surface timely insights across OpenSea.

How do verification and safety signals work?

You’ll see blue checkmarks next to verified accounts and badges on notable collections. These are signals to help you assess authenticity and interest; they aren’t endorsements or guarantees. Always review contract addresses, creator details, and your wallet prompts before confirming. To find out more, visit What is a verified account or badged collection? 

What kinds of things can I buy or sell using OpenSea?

Just about any onchain item, including art, PFPs, music, gaming items, membership passes, domains, and more, each represented as an NFT that proves ownership and provenance on the blockchain, in addition to tokens. Though we start by embracing a permissionless ethos, we may block certain items that violate our Terms of Service, such as when we learn an item poses a risk to users.

How does Ethereum fit into all of this?

Ethereum is the largest NFT ecosystem, known for smart contracts and broad wallet/tooling support. Many OpenSea actions happen on Ethereum or its L2s; improvements like L2 scaling and data “blob” availability (EIP-4844 / proto-danksharding) aim to reduce costs and increase throughput over time.