Frequently Asked Questions

Everything you need to know about OpenSea

General Information

  • What is OpenSea? +
    OpenSea is a decentralized marketplace for crypto assets, which include collectibles, gaming items, and other digital goods that are backed by a blockchain like Ethereum. On OpenSea, you can buy or sell any of these items through a smart contract, meaning that no central authority ever holds custody of your items. You can even check out the source code for this smart contract here.
  • What can I do on OpenSea? +
    OpenSea lets you buy and sell crypto collectibles, gaming items, and other blockchain-based digital items. To start, you can go to your account page to view all of your items (OpenSea supports over 60 different item types, and growing!) If you want to sell one on the market, simply click into it and click "Sell".

    Additionally, OpenSea is often useful for browsing the many types of digital collectibles. We offer a powerful searching and sorting mechanisms that lets you easily find the items you're looking for.
  • What exactly are these items I see on OpenSea? +
    All of the items you see on OpenSea are blockchain-based digital items. Some people like to call them non-fungible tokens, or NFT's. Each item is uniquely owned by an Ethereum address and live on the blockchain. Excitingly, they can be viewed anywhere, exchanged openly, and truly owned in a way that was never before possible in the digital world. You can read a little more about the idea of true digital ownership in this blog post.
  • What if I want to create my own item on the blockchain? +
    Glad you asked! If you're developing your own smart contract for a game, digital collectible, or some other project with unique digital items on the blockchain, you can easily get added to the OpenSea marketplace. Just follow the steps in the OpenSea developer documentation. More info on what OpenSea provides can be found on our developer page.

    If you're a creator, influencer, or streamer and wish to list something on OpenSea, reach out to us at [email protected].

Getting Started

  • What do I need to use OpenSea?+
    If you're on a desktop computer, you'll need to install MetaMask in your browser in order to use OpenSea. You'll also need to fund your account with Ether in order to purchase an item on OpenSea.

    On your mobile device, you'll need to use an Ethereum-compatible mobile browser like Trust, Coinbase Wallet, Vault, or Opera.

    To learn a little more, check out our getting started page.
  • Getting MetaMask+
    You can install MetaMask in your browser from the MetaMask website. A great video can be found on MetaMask here.
  • Why is my my MetaMask account locked?+
    If you see a lock screen on your account, you simply need to unlock MetaMask. You can do this by clicking the MetaMask fox in the upper right section of your browser and typing your password.
  • Selling

  • How do I list an item for sale?+
    In order to list an item, you'll need to go to the item on your account page. On the item detail page, click "Sell". This will walk you through the steps for selling an item. Note that the first time you auction an item, you will need to complete several MetaMask transactions in order to give the exchange contracts access to your items. After you complete these initial steps, creating an auction will only require signing a MetaMask message. This means that you can auction items without paying gas.
  • How does the auction work?+
    As an OpenSea user, you can either sell an item for a fixed price, or use an auction mechanism. When you list an item for auction, you specify a start price, end price, and duration. At any point, someone can buy your item at the current price. The current price starts at the start price and gradually decreases over the auction duration until reaching the end price. After the specified duration, the auction will expire and no longer be available for purchase.
  • Can I make an auction that doesn't expire?+
    Currently, all declining-price auctions expire when the expiration time is reached. However, if you create a fixed-price auction, it will not expire.
  • What happens to my item when it's on auction?+
    For most types of items, the item remains in your wallet while it's on auction! This means it can still be used in the game while it's on auction on OpenSea. (Note that there are still a few item types that require escrow, however)
  • In order to list an item for sale, what transactions are required?+
    OpenSea's auctioning system minimizes the number of on-chain Ethereum transactions required to list an item for sale. In fact, once you've completed the preliminary steps, auctioning an item will require no on-chain transaction at all. Here's how it works:

    1. For your very first OpenSea auction, you will need to initialize your account with a free (plus gas) on-chain transaction. You only need to do this once!

    2. When you auction a new "type" of item (for example, your first CryptoKitty or your first CryptoStriker), you will need to complete another free (plus gas) transaction in order to unlock access to that item type. In most cases, you only need to do this once per item type! So, for example, once you've approved access to CryptoStrikers, you can auction as many CryptoStrikers as you like without having to complete another transaction.

    3. Once you've unlocked access to that item type, all auctions are simply a Metamask signature. No gas required!

    We've worked very hard to reduce the overall gas required to use OpenSea. While there are a few transactions up front, the overall result is a much cheaper, faster experience for the end user.
  • Can I gift or transfer an item to another wallet?+
    Yes! You can transfer or "gift" an item by clicking the "Gift" button when viewing it.

    Gifting an item requires a small amount of gas to pay the Ethereum network, but is not subject to any other fees.
  • Can I sell multiple items at once?+
    Yes! You can sell a "bundle" of items by going to your "My Account" dropdown and selecting "Sell a Bundle". This will allow you to add multiple items in one single auction.

    Selling a bundle of items does not require gas! As with other auctions, the first time you sell, you will need to initialize your account with an on-chain transaction. Also, when you auction a new "type" of item (for example, your first CryptoKitty or your first CryptoStriker), you will need to complete another free (plus gas) transaction in order to unlock access to that item type.

    When someone buys your bundle, he or she will receive all of the items in the bundle, and you'll receive your payment!
  • Can I send multiple items at once to another wallet?+
    Yes! You can transfer or "gift" a bundle of items by going to My Account and selecting "Gift an Item Bundle". This will allow you to add multiple items in one single transfer.

    Gifting a bundle of items requires gas, but will only be one transaction if you've already approved the assets for transfer. Each bundle is limited to around 40 items due to Ethereum's gas limit.

    Gifting items is not subject to any fees.
  • Making and Accepting Offers

  • How do I make an offer for an item I want to buy?+
    See an item you'd like to buy? Simply click the "Make an Offer", which will allow you to specify the price you're willing to buy the item. By bidding like this, you will automatically pay for this item if the owner accepts your offer, unless you cancel it. Read more about how this is useful on our blog.

    If you're bidding for the first time, there will be a few preliminary steps before you can submit your offer. While these steps may be a little cumbersome, keep in mind these will only happen once! You will need to:

    1. Wrap your ETH with W-ETH (wrapped Ether) using the W-ETH station on the right hand side in the bid flow.
    2. Approve the exchange to access your W-ETH.

    Both of these will require submitting transactions to the blockchain, but after that submitting an offer does not require gas! Each time you want to bid, you simply sign a message which specifies the price you'd like to purchase the item at.
  • How many offers can I make at a time?+
    You can pretty much make as many offers as you want!

    For example, say you have 1 ETH in your account. If you wrap that ETH (turning it into 1 WETH), you could bid 1 ETH on CryptoKitty #123, 1 ETH on CryptoFighter #345, 1 ETH on a Mythereum card. However, the moment that any of your bids gets fulfilled, the other bids for 1 ETH on the other items would no longer be valid (since you no longer have enough WETH to fulfill them).
  • I see some offers on an item I own. How do I sell my item to the highest bidder?+
    First of all, congrats! You're well on your way to selling an item. Read more about how this is useful on our blog.

    You can sell your item to the highest bidder by clicking "Accept Offer" on the highest offer. If you're selling an item for the first time, there will be a few preliminary steps. While these steps may be a little cumbersome, keep in mind they will only happen once!

    You will need to:

    1. Allow access to offers. You'll need to initialize your account in order to sell items. This will be an on-chain transaction. Fortunately, this only needs to be done once!
    2. Approve access to the item type. This will require another on-chain transaction, but only needs to be done once per item type (i.e, once for CryptoKitties, once for Etheremon, etc.)

    After completing these two preliminary steps, you can then complete an on-chain transaction to sell your item! Once you complete the transaction, you will have W-ETH in your account. You can either leave your W-ETH as is (it's useful for bidding on other items), or you can turn it back into Ether on the Offers section of your account page.
  • Someone offered me DAI or USDC for my item... what is this currency?+
    Congratulations! DAI and USDC are ERC-20 tokens with some remarkable qualities. First of all, they're stablecoins, which means that their value is protected against some of cryptocurrency's notorious price swings. This is not the case for all stablecoins, but each is pegged to the price of one US Dollar. They won't always have that exact value, but you can rest assured that they will stay within a few percentage points of that mark.

    Dai (DAI) is a decentralized stablecoin with smart contracts backed by collateral. For more information, check out this video from Dai's creator Maker about how Dai maintains its price.

    USD Coin (USDC) was crafted by the CENTRE consortium, founded by Circle and Coinbase. Users in the U.S. can easily convert their USD to USDC on Circle or Coinbase for free and transfer it to their wallet of choice to complete their purchase on OpenSea.

    In short, stablecoins are tokens worth a dollar each. When you see DAI or USDC, think dollar.

    So, if you're convinced of the value of stablecoins (we are!), you can sell your item to the highest bidder by clicking "Accept Offer" on the highest offer. If you're experienced at selling on OpenSea using ETH, it'll be a familiar process. If it's your first time selling an item, you'll need to go through a few preliminary steps:

    1. Allow access to offers. You'll need to initialize your account to sell items. This requires an on-chain transaction, so you'll have to pay some gas. Fortunately, it only needs to be done once!
    2. Approve access to the item type. This will require another on-chain transaction, but it only needs to be done once per item type (i.e, once for Axies, once for Etheremon, etc.)
    3. Complete a final on-chain transaction to sell your item. Once you complete the transaction, you'll have DAI or USDC in your account. What you do from there is up to you!
  • How do I get notified when someone bids on my items?+
    We'll email you whenever someone bids on an item you own. Just make sure you have an email set in your Account Settings.

Common Issues

  • Help! I was able to auction things before, but it's not working anymore!+
    Occasionally, Metamask will start having issues submitting transactions, causing the OpenSea flows to fail. We've found that the best solution for this is to kill the Metamask extension in Chrome. Before doing this, ensure that you have backed up your Metamask seed phrase. Once you've backed up your seed phrase, try the following:

    1. In Chrome, go to the "window" menu, and click "Task Manager".

    2. Find the Metamask processes (you can sort alphabetically) and hit "End Process".

    2. When the white Chrome notification pops up that says "Click this ballooon to reload the extension", click it to reload Metamask. (If you're not able to click the white notification in time, simply go to chrome://extensions and click "Reload").

    3. Then give the flow on OpenSea another try.

    If you're still having issues reach out to us on Discord
  • I bought something on OpenSea. It's in my OpenSea account but it's not showing up in the game where it's used.+
    In these cases, we recommend reaching out to the game's support team. If the item is showing up properly on your OpenSea account, the blockchain has properly recorded its transfer into your account. However, the game may not have properly updated to reflect the new ownership (hence we recommend contacting their support team).
  • I can't see my Gods Unchained cards on OpenSea.+
    Gods Unchained employs a mixed system of on chain and off chain asset management. Cards remain off chain and invisible to OpenSea until they're activated. For more information on what activation means, check out the Gods Unchained Quick Guide on Activiation.

    To activate your cards and make them viewable on OpenSea, go to the Gods Unchained Activate page and follow the prompts. After your activation transaction has been mined, your cards will appear on your OpenSea account page.
  • I'm getting the error: "Unable to match offer with auction. Please restart your wallet/browser and try again!"+
    Occasionally, MetaMask's node will get out of sync with the blockchain, which will prevent you from completing auctions. If this error persists, we recommend switching your RPC provider to a different Ethereum node. To do this, go to MetaMask and click on "Main Ethereum Network". Then switch to "Custom RPC". You'll need to get a custom URL from our Discord channel.

Developer FAQ's

Please visit the Developer FAQ's section of our developers portal for a comprehensive list of developer FAQ's.

Other Questions

  • Is OpenSea just aggregating auctions from other marketplaces?+
    While OpenSea does include data from specific game marketplaces (like CryptoKitties), most of the auctions you'll see on OpenSea are made through our own auctioning system. For many games, we act as the primary marketplace for buying and selling the game items.
  • Do you charge transaction fees?+
    Yes, we take 2.5% from the price of a successful sale. If we have an official partnership with the original creator of the item (such as the developer of the game), the original creator can also opt to take a fee on the final transaction as well.

    There's no fee to list items or buy items. But when you list an item, the sidebar on the right (or the section on the bottom on mobile) will tell you fee that will be deducted when the item sells. E.g. if OpenSea takes 2.5% and the creator takes 4%, the total fee will be 6.5% of the final sale price.
  • Is OpenSea safe?+
    OpenSea has a strong track record as a safe marketplace for unique blockchain-based assets. We've had over 4,000 ETH of volume pass through our smart contract and many thousands of successful sales. We've acted as the primary marketplace for several large games, including Etheremon Adventure, My Crypto Heroes, CryptoVoxels, ChainBreakers, Ether Kingdoms, and CryptoBeasties -- as well as a secondary market for CryptoKitties, MLB Crypto, Axie, and a host of others.

    For the more technically savvy: we leverage the Wyvern Protocol, an audited, battle-tested set of smart contracts. Wyvern is a decentralized exchange system that creates a personal proxy for each user. We don't control the proxies that get created, and you have to approve access to each ERC721 contract individually. Once the contract is approved, the logic of the exchange contract only allows it to transfer an asset from your proxy only if A) you have signed an order indicating you wish to sell that item, and B) it is properly matched by a buyer paying the appropriate funds. So not only does your asset not leave your wallet until it is sold, it is only allowed to be swapped if an order you create is properly matched.
  • What exactly happens when I list something for auction?+
    When you list one of your collectibles for auction, you'll sign a message broadcasting that you're willing to sell the item for a specific price. Once your item has been placed for auction, a buyer can buy your item at the current auction price. At that time, the proper Ether amount will be transferred to you and the item will be transferred to the buyer. Excitingly, this happens atomically -- meaning there is no risk that you don't receive payment or that the buyer doesn't receive the item.
  • What's the story with support for ERC-20s like MANA and DAI?+
    When we first built OpenSea, we decided to construct the experience around Ethereum, as a dapp platform and as a currency. It was the simplest option. Because most users already had some ETH, if only to pay gas, it provided an economic lingua franca. And it allowed us to streamline a new and unfamiliar buying experience. But all along, we’ve been excited about the entire token economy and we intend to grow with the maturing ecosystem and userbase.

    Now, with support for ERC-20 tokens like MANA and DAI, we're doing exactly that. In addition to allowing users to spend the currencies they already have, it will allow developers to offer NFTs for sale denominated in the dapp's in game currency. You still get to use all the OpenSea features you've come to know, but now with more flexibility.

    You'll find some items listed for sale in an ERC-20 token. You can buy them immediately by paying in the specified currency, like making a purchase with ETH. If you don't have any of the seller's specified currency (and have no desire to acquire any), you can make an offer in the currency of your choice by clicking the 'Make Offer' button and selecting your preferred currency from the dropdown next to the entry field. For more about how powerful bidding on OpenSea is, check out our Medium post.

    To list an item for sale in the ERC-20 of your choice, click 'Sell' on the item's page, select a token from dropdown next to the price entry field, specify your desired price, then click 'Post Your Listing'.
  • Do you issue refunds?+
    Since transactions on the blockchain are irreversible, we cannot provide refunds. We have no ability to cancel, revert, or modify any transactions on the Ethereum network.


We're always happy to help with code or other questions you might have! Contact us via [email protected] or chat with us and other developers in Discord on the #developers channel.

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