OpenSea is the world’s first and biggest NFT marketplace launched in 2017. It’s a decentralized community: all assets, wallets, and addresses, as well as decision making, are governed entirely by the users. The marketplace supports the Ethereum, Polygon and Klaytn blockchains (only the first two for minting).
The OpenSea NFT protocol uses ERC721 and ERC1155 standard tokens (for collections). You can pay with any ERC20-token here, or NFTs buy directly with a bank card via MoonPay.
The collection features a wide range of categories including art, sports, trading cards, and projects from prominent artists. You can also buy NFTs for music, domain names, or 3D objects here.
OpenSea is also available as an iOS app.
The platform has a flat 2.5% fee on each transaction, paid by the buyer. More on the fees in the final section.
The main page of OpenSea has a search bar, a dashboard, and a browser of all the NFTs on the platform. Scrolling down, you’ll see hot collections, trending, and info about ongoing drops. Even further down the page, you’ll see “Resources for getting started” with some helpful newcomer info and also a browser by category.
In the top-right menu, you can quickly access all the same features as well as your profile dashboard.
To get going on OpenSea, you don’t have to register — just link your crypto wallet in the top-right, and you’re good to go.
The platform currently supports 13 wallets, including MetaMask, Coinbase Wallet, WalletConnect, Fortmatic, Kaikas, and more. Opera Touch and Trust wallet are mobile-only.
Select the desired wallet and confirm log-in. The wallet will ask for a digital signature, and then you can go to your profile page. Complete your profile there with a name, a profile pic, background design etc. Once done, you can create your own favorites collections and view statistics.
OpenSea: How to buy NFTs
If you wish to buy an NFT, simply click on it anywhere you see it.
A buy page will open. Here, you can check the description in the left section below the picture and all the deal details — on the right.
OpenSea has two price types: Set Price and Auction with Buy Now option.
If the token is up for auction, then you’ll see the details of the price, time (with expiration date), and bid and listing history. By clicking the Like button, you’ll see all the users who added the item to favorites.
To buy the token, make sure you agree with the price or the latest bid. Place yours or click “Buy”, then confirm the transaction.
How to create NFTs on OpenSea
To create an NFT, head over to the “Create” section in the top-right. Before proceeding, confirm the network signature in the wallet. After that, a token creation form will open.
Drop your file in the file section, then enter its name.
Next, add a description and an external link.
In the second half of the page, you can make your token a part of a collection. For that, hover the mouse pointer over the (!) sign, and go to “Manage my collections” (also available through Profile settings in the top-right).
A window will open where you’ll need to enter the details of the collection, set your royalties (up to 10%), choose the blockchain, and then the visual layout. Once done, tick the box if the content is NSFW (18+), and then click “Create”. You can also import existing collections from other major NFT marketplaces, such as Rarible, Mintable, and others, and even choose to mint one there.
You can also add some advanced features here, such as Properties (e.g. Gender -> Male), Levels of rankable traits (e.g. Speed = 3 out of 5), and Ranks (shown as numbered stats).
Also, you can attach unlockable content (only available after purchase) and rate the content as sensitive/NSFW if necessary.
The “Supply” field allows you to create multiple copies of the same item (only available for Polygon).
Once all the fields are filled, choose the blockchain, and click “Create”.
OpenSea charges two fees when minting your first NFT on Ethereum. One is called “initialization fee”, and its purpose is to confirm that you’re willing to sell on OpenSea. The other fee is for your actual first listing, and it doesn’t occur again. Make sure you agree with the fees before finishing off and click “Create”.
Your NFT is now ready for sale.
How to sell NFTs on OpenSea
You can sell your NFT immediately after minting or later on from the Profile tab in the top-right of the main page. Select the item you want to sell and click on the “Sell” button.
Choose the price type (Set Price or Auction/Highest Bid). Choose whether you want to bundle the token with others. Then set your price and, if necessary, some listing specifics, such as the ending (expiration) price and/or schedule the listing for the future. You can also choose to make it either public or only available to a certain buyer.
Once done, double-check everything and click “Post”. Your token is now up for sale.
A note on the fees on OpenSea
As said before, OpenSea has a flat 2.5% fee on all transactions. However, Ethereum users will have to pay a number of gas fees on top.
As an author, you’d have to pay gas at least twice: when creating and listing your first NFT. Also, if you’re running an auction, you’d be paying gas each time you accept a bid.
When setting your price, make sure you agree with the current gas fee and that your minimal bid’s high enough to cover it. You also have to pay gas whenever you cancel a listing as this requires a transaction, too.
Also, keep in mind that bids on OpenSea are only accepted in WETH (Wrapped Ether), and that it requires gas every time you convert your WETH into ETH.
As a buyer, you pay gas each time you buy an NFT (or cancel a bid, as this also takes a transaction).
Mind that the above applies to Ethereum only. Polygon does have its own conversion fee, but its size is usually negligible, and it also allows you to mint gas-free. If you want to mint free and trade near-free, best go for Polygon.
Final Word On OpenSea
OpenSea has dominated the NFT world since its inception in 2017. It boasts a plethora of different NFTs available, and many franchises and independent artists view OpenSea as their #1 marketplace. It beats its nearest rivals by a large margin in terms of volumes, transaction count, and overall turnover, and there’s every chance it’s going to stay that way for quite a while.