What is OpenSea?

A simple explanation for beginners. What is Opensea – How the largest marketplace for NFTs works and is used for.

What is Opensea?

Opensea is currently the largest marketplace for NFTs. Users can buy, sell and list NFT collections on different blockchains.

Opensea features NFTs for:

  • Images
  • Videos
  • Sports cards
  • Virtual worlds
  • Gaming items
  • Collectible
  • Domain names
  • Art

OpenSea categorizes and shows data for NFT collections on Ethereum, Polygon and Klaytyn.

How to use OpenSea

Users connect with their crypto wallet and the NFTs are traded between users’ own wallets.

OpenSea is a non-custodial marketplace so you as a user are in control of your funds and NFTs.

Many users that buy and sell on OpenSea don’t know that NFTs are taxed. Koinly (affiliate) is a crypto tax software that does most of the work for you.

What is an NFT collection?

An NFT collection is a set of NFTs starting at 2 pieces or more. The creator of the collection makes several pieces and determines their traits and scarcity in relation to each other. These properties are added to an NFT contract. The contract can be coded from scratch or created through a marketplace.

When creating a collection users can choose to:

  • Import a contract
  • Create
  • Mint on other NFT marketplaces
opensea nft collection

More on creating your own contract in the documentation.

The contract is deployed to the blockchain, for example Ethereum or Polygon. The pieces in the collection are then minted from the contract.

What is Opensea floor price?

The floor price is the lowest price one or several NFTs in a specific collection are listed for.


  • The floor price of a collection is 0.2 ETH
  • Sweeping the floor means someone buys all NFTs at the floor.
  • This creates a new floor price of the previous second lowest price.

Is OpenSea safe?

what is opensea

As a buyer or seller on you are in control of your assets through your own wallet. So as long as you take computer security seriously it’s pretty safe. There have been a few bugs with listings and similar on the platform, but nothing major.

However many people who lose their NFTs or get hacked do not understand computer security. You should be careful with what links you click, what you install on your computer and never type your seed phrase or private key on any website ever.

Consider using a hardware wallet like Trezor (affiliate) connected to your Metamask.

How do you cash out on OpenSea?

OpenSea is a non-custodial platform which means that you are in control of your own account and funds. So to cash out you need to send the crypto from your own wallet to an exchange (like Coinbase or FTX) where you can withdraw the currency of your choice to your bank account.

The cashing out has nothing to do with OpenSea. It’s just your wallet.

Can you use OpenSea with Coinbase?

Yes. But not from the Coinbase website.

You can connect to OpenSea with a Coinbase Wallet (browser extension) and can send funds from Coinbase to your wallet.


Read more about how to buy and how to sell.

What is gas on OpenSea?

Gas is what Ethereum requires to send transactions and perform actions on the blockchain. It’s just ETH but in another unit called WEI or GWEI.

Gas is used to prevent spamming on the network. And is a market with supply and demand mechanics. When a lot of people want to use the network at the same time (like minting a popular NFT) the price goes up.

Gas for a simple transaction of a token to another wallet can be anywhere between $3 – $50. More complex actions like trading or listing can be a even more.

On Etherscan you can see the current gas price and what different types of transactions currently cost.

Q & A

Is there an OpenSea coin?


Many projects in the crypto space have released tokens and some have been airdropped to users retroactively. So there has been a lot of anticipation around the OpenSea token. There has not been any official statements or releases about this yet though.

What network does OpenSea use?

OpenSea uses Ethereum, Polygon and Klaytyn blockchains. With Ethereum currently being the most popular.

Is OpenSea decentralized?

There has been some debate about OpenSea not being very decentralized. The team makes all the decisions and changes.

Decentralization is a sliding scale. Compared to other protocols in crypto and DeFi it’s probably one of the more centralized ones. But it is still non-custodial and the users hold their own assets.


Affiliate: Learn more about blockchain and crypto with courses at Skillshare.