What is OpenSea?
Founded in November 2017, OpenSea is today the largest marketplace for crypto collectibles with over 300+ asset types and 10,000,000+ digital assets on the market.
You can bid on, buy and discover lots of crypto collectibles as well as sell your own crypto collectibles on OpenSea. Collectibles of many popular blockchain games such as CryptoKitties, Gods Unchained and Axie Infinity are available on OpenSea.
OpenSea is not just a good place to trade crypto collectibles, but also a good place to discover many different blockchain games and digital assets.
More importantly, as crypto collectibles are not fungible assets like Bitcoin or Ethereum, users can get an idea about the value of non-fungible assets through OpenSea. If you are a developer, you can also create your own marketplace for ERC721 or ERC1155 assets on OpenSea.
Beginner’s guide to OpenSea, How to use OpenSea to buy, sell and bid on crypto collectibles
In order to use OpenSea, you first need to install MetaMask in your browser. MetaMask is a browser extension which allows users to interact with Ethereum dApps in their browser.
MetaMask is used by many people to access dapps such as decentralized exchanges and blockchain games. You can also get a Ledger Nano X or Trezor Model T to use in conjunction with MetaMask for a greater security.
You can simply add MetaMask to your browser from Chrome Web Store or Firefox Add-ons. After adding it to your browser, you can follow the steps below to install your wallet.
Step 1. After adding it to your browser, click on MetaMask icon and click continue.
Step 2. Create a strong password, you will use it to log into your MetaMask wallet.
Step 4. Write your secret backup phrase on a paper or download it as a txt file (not recommended). Click next and confirm your backup phrase.
If you remove MetaMask from your browser, you will use this phrase to restore your wallet. You can log in to your wallet just typing the password you created in the second step.
For every kind of cryptocurrency wallets including hardware wallets, you need to get a copy of your backup phrase and keep it in a safe place. Instead of writing down your backup phrase on piece of paper, you can use CRYPTOTAG which is a backup solution made out of titanium.
How to buy a crypto collectible on OpenSea
Click on ”browse” and choose a category or view all, then you can pick an item to make an offer for.
After picking the item, enter your offer and click to continue. Before making your first offer, you should convert your ETH to WETH and also allow OpenSea to access your WETH when a sale occurs. These transactions only require gas and will not be required again.
You can make an offer for collectibles that are not even on sale, which is a very good feature for sellers who can’t simply set a price for their items. Moreover, you can make an offer for more than one items with the same ETH.
How to list a crypto collectible for sale on OpenSea
Transactions for selling a collectible will happen off-chain, but you again need to do some on-chain transactions before starting: Once to initialize your account, and to unlock access to an each item type.
So if you are going to sell a Gods Unchained card, you first need to unlock this item type with a free (only gas) transaction. That’s it, after you completed these steps, you can auction every card you have for free.
The picture below shows an OpenSea account. You can see your collectibles under your account / your items and sell them by clicking ”sell”. You will set a fixed price for the item or use the auction mechanism.
All assets are also biddable, so you don’t necessarily need to price your item. Besides that, depending on the item, you can use some of them in games while they are on auction.
OpenSea takes 2.5% fee from every successful sale. An additional fee may be taken by the developer of the game as well.