Welcome to OpenSea

by Dan Viau

Welcome to OpenSea! We’re the largest marketplace for non-fungible tokens (NFTs). Non-fungible tokens are unique, digital items with blockchain-managed ownership. Examples include collectibles, game items, digital art, event tickets, domain names, and even ownership records for physical assets.  In other words, we’re kind of like eBay for CryptoKitties.  Using OpenSea, you can buy, sell, and explore millions of assets across hundreds of categories.  If some of that sounds unfamiliar, don’t worry!  By the end of this article, you’ll have the knowledge and skills to effortlessly move through the world of NFTs.

Getting Started

Perhaps you’ve discovered a blockchain game you want to play and you need some NFTs to get started.  Maybe you’ve spotted a piece of digital art that you just can’t live without.  Maybe you just want to ram around and see what all the hype is about.  Whatever your reason, we’re here to help you get started on the right foot.

The first thing you’ll need is a wallet.  In the brave new world of web 3, a wallet is not just a folded piece of leather where you store your credit cards and paper money.  In this context, a wallet still stores your digital money, but it also handles your identity, your credentials, and more.  Not only does it manage access to the items you own, it allows you to broadcast transactions to the blockchain.  In some ways, it’s more like a Swiss army knife than a wallet.  Key takeaway: a wallet is a tool you add to your browser to interact with the blockchain.

Why do you need a wallet before buying and selling on OpenSea?  Because OpenSea itself is another tool you use to interact with the blockchain–no walled gardens or kids’ table stuff here.  We never take possession of your assets.  Instead, we provide a system for peer to peer exchanges.  Since you’ll be using OpenSea to interact directly with others on the blockchain, you’ll need a wallet to help you turn your actions in the browser into transactions on the blockchain.

A few quick notes on terminology.  A wallet is different from an address, which is different from an OpenSea account.  A wallet is a complex tool that, among other things, helps you create and manage addresses.  An address is a 42-character hexadecimal string that roughly corresponds to a unique location in the Ethereum network.  If the previous sentence wasn’t packed with enough technical details for you, check out this excellent post on Stack Exchange.  If, on the other hand, it left you scratching your head, just know that an address is an identity in the web 3 world.  Your Ethereum address serves a similar function to your email address in the PayPal context. 

An OpenSea account is a bundle of supplemental information, stored on OpenSea’s traditional servers, attached to an address.  Key takeaway: you don’t store NFTs in your OpenSea account.  They’re owned by an address on the blockchain.  You, in turn, own the address by exclusively controlling your private key or seed phrase.  An OpenSea account just provides a bright and cheerful lens to view the cold, binary reality of the blockchain.

Choosing Your Wallet

Lots of skilled teams are working independently on building different wallets.  They all serve the same purpose, but each one takes a different approach and makes different tradeoffs.  If you’d like, you can try a few different wallets to determine which works best for you, but make sure to give MetaMask a shot.  It’s my favorite by a mile.

MetaMask – A browser extension with peerless power and flexibility. MetaMask is web 3’s most popular wallet and one of the oldest players in the industry. 
Fortmatic – A user-friendly wallet from an innovative team that allows you to sign up with your phone number from any device.
Authereum– A usability-focused wallet with no transaction fees and a fiat on-ramp.
Dapper – A browser extension that pays gas fees for you.  More on the concept of gas later.
Bitski – A simple-to-use wallet allowing users to sign up with an email and password.
Torus – A low friction wallet that allows you to login with Facebook, Google, and other OAuth providers.

Check out this MetaMask Introduction Video to get a sense of the installation process.  It only takes a few minutes to install.

Once you’ve got your wallet set up, it’s time to hook it up to OpenSea.  Click here to navigate to your account page.  At the top, you’ll see a notification indicating your wallet is not yet connected.  No sweat, that’s expected behavior.

Click the green “Unlock your wallet” button to trigger a wallet popup, then use your wallet’s user interface to unlock your wallet.  It’ll likely be a button that says something like “Unlock Wallet,” “Unlock,” or “Connect.”  You might have to enter your password and accept some terms and conditions, too.

Once you’ve got your wallet unlocked, you’ll be able to see your assets (if you already own some) in your wallet on your OpenSea account page.  You’ll also be able to change your OpenSea account settings on the account settings page

Now that your wallet and OpenSea are playing nicely together, you’ll need to get some ETH to pay for gas and items.

Getting Ether

Another quick digression into terminology: Ethereum is the whole shebang.  That term describes the blockchain and everything that makes it tick.  Sometimes we say “the Ethereum network” instead of “Ethereum” to make it clear that we’re not talking about Ether.  Ether is the native currency of the Ethereum network and it’s commonly abbreviated to ETH, which is its ticker symbol.  You use ETH to pay gas fees and as money.  

Gas fees are a bit of a tricky concept.  If you’re interested in the technical details of gas, read Jeff Coleman’s Stack Exchange post about it.  In his words of his TL;DR, “Gas is the way that fees are calculated. The fees are still paid in ether, though, which is different from gas. The gas cost is the amount of work that goes into something, like the number of hours of labour, whereas the gas price is like the hourly wage you pay for the work to be done. The combination of the two determines your total transaction fee.”  Bottom line: you need ETH to pay for some of your interactions with the blockchain and to pay for the items you buy. 

Don’t worry that gas fees will break the bank, though.  Most actions on OpenSea only cost a few cents, if they cost anything at all.

So, where can you buy ETH?

Coinbase – The biggest exchange in the business.  Most people who want to turn their Dollars into cryptocurrencies turn to Coinbase.  Follow the trail starting here, and you should have some ETH within a few days.

Fortmatic – Users can purchase up to ~$150 worth of ETH using a credit card, without verification or much waiting. For more information, check out their recent blog post.

Your OpenSea Account Page – Depending on your geographical location, you might be able to buy ETH using the “Add funds” button in the top right corner of your OpenSea account page.

No matter what other tokens you end up dealing with over the course of your journey, ETH will be your entry point and your fuel.  So make sure to stock up.

Searching for Items

The heart of OpenSea is the Browse page.  If you want to find things to buy, it’s your first stop. When you arrive, you’ll see something like this:

If you know the name of the item you’re searching for, type it into the white search bar with the placeholder “Search all items and bundles” and press enter.  If not, read on to learn about our sorting and filtering options.  They’ll help you discover the kinds of things you’re looking for and might even show you a few irresistible surprises along the way.

By default, we show trending items from the top collections at the top of the search results, but you can refine and sort the results in many different ways.  Here are some of the sort options that we offer:

Recently Listed- The items that have been listed for sale most recently will appear first.
Recently Born- The items that have been minted most recently will appear first.
Expiring Soon- The items with auctions that are ending soonest will appear first.
Lowest Price- The least expensive items will appear first.
Highest Price – The most expensive items will appear first.
Highest Last Sale- Items will be ordered by the price at which they last sold.  Items that have sold for lots of ETH will appear first.
Oldest – The items that were minted the longest time ago will appear first.
Most Viewers- The items that have been visited by the greatest number of users will appear first.

In addition to sorting search results, you can filter results in a variety of ways.  Click on the name of a collection in the sidebar to filter for assets belonging to that collection.  You’ll see something like this:

Once you start filtering by collection, a variety of other filtering options will appear.  You can filter for items on a specific token contract within the collection, for listings denominated in a specific currency, for items that all share a trait, or for items in a specific token ID range.  Spend a few minutes playing around with the checkboxes and sliders to get a sense of how the filtering works.  If things start going awry, you can reset by clicking the X in the top right corner of the sidebar or clicking on the “Browse” option in the navigation bar.

Don’t overlook the six special status pills at the top of the sidebar:

On Sale – Clicking this pill will limit results to items that are currently listed for sale.  Clicking it again will turn the filter off.  Unlike eBay, OpenSea shows lots of items that aren’t for sale.  So, if you’re in a buying mood, make sure to click this pill.
Has Offers – Even when an item’s not on sale, OpenSea users can make offers on it.  Clicking this pill will limit results to items that have standing offers on them.
Pre-Sale – Sometimes, developers use factory contracts to sell items before a game is released. Clicking this pill will filter for pre-sale items and other items that are sold by factory contracts.  When you purchase an item from a factory contract, it mints you a new NFT, right there on the spot.
Has Bounty – OpenSea users can earn bounties by referring buyers to listings on OpenSea. Learn more about bounties here.  Clicking this pill will limit results to items that present bounty-earning opportunities to referrers.
Auctions – Filters for items that have active English auctions.  Instead of buying these items immediately, you’ll place a bid and hope you’re the top bidder when the auction ends.  Less immediate gratification, more bargains.  More on English auctions below.
Bundles – Filters for listings that contain multiple items.

By searching, sorting, and filtering, you should be able to find some tempting NFTs.  If it’s your first time buying an NFT, I recommend selecting something cheap and cheerful to test out the system with.  Now that you’ve got your item picked out, how do you make a purchase?

Buying Fixed Price Listings and Dutch Auctions

OpenSea allows sellers to create a few different types of listings: fixed price listings, Dutch auction listings, and English auction listings.  The buying process is a little bit different for each type of listing.  We’ll get into more detail about listings below in the section focused on creating listings.

But first, let’s take a look at the fundamentals of fixed price listings and Dutch auctions. A fixed price listing is like what you’d see on Amazon.  A seller picks a price, confirms the listing, and the item remains on sale until it’s either purchased for the stipulated price or cancelled by the seller. 

A seller can create a Dutch auction by selecting a starting price, ending price, and an auction duration.  The seller starts the auction at a level above the expected demand, and the price declines over time.

For now, all you really need to know is that both of these types of listings can be fulfilled immediately.  Just click the “Buy now” button and follow the prompts from your wallet provider.  

If it’s your first purchase, you might be asked to do some initialization transactions.  But when you see a highlighted window that says “Completing the trade…” on OpenSea and a wallet popup, you’re in the home stretch.  Click “Confirm” to commit to the purchase.  When the transaction is confirmed, you’ll be the proud new owner of an NFT.  If, for some reason, the transaction fails, you don’t lose the purchase price.  Either the whole deal happens or none if it does.  But don’t worry, they almost always succeed.

The structure and the purchase process of a fixed price listing is almost identical to what’s described above, except that the price will not get lower over time.  Just apply the principles above.  Next, we’ll look at English auctions.

Bidding on English Auctions

An English auction normally just goes by the snappier name “auction.”  It’s the type that comes to mind when one thinks of eBay, cattle, or highbrow art auctions.  We’ll dive into the details of how English auctions work on OpenSea in the selling section below. But for now, just beware that you’ll need 1) some WETH and 2) a little patience.

To make a bid on an auction on OpenSea, you’ll need to convert some ETH to WETH first.  WETH is an ERC20 token that’s pegged to the price of Ether.  For more info on WETH, check out this helpful site by the makers of Radar Relay.  The good news is that you convert back and forth between ETH and WETH right on OpenSea.  Just visit the offers tab of your account page and use the WETH station on the right.  Enter a value in the ETH box and click the “Upgrade” button to get some WETH.

You’ll need to wait for the WETH conversion transaction to confirm.  Once it does, you’ll see that some of your ETH balance has been converted to WETH.  Now, you can take that WETH to the page of an item that’s on auction and place a bid.

To place a bid, enter a bid equal to or higher than the minimum bid in the bid input field, then click the continue button.  You’ll be redirected to a page where you confirm your bid.  Click the “Confirm bid” button and follow the prompts from your wallet to make your bid.

Now that you’ve placed your bid, keep an eye on the auction.  If you’re the highest bidder when the auction ends, you’ll receive the item.  No more action is required from you.  We’ll handle the transfer of goods and funds.  If you’ve set up an email on the account settings page, we’ll even email you to let you know the good news. 

Now that you’ve got a couple NFTs, you ought to know how to resell them.  Let’s look at the selling process next.

An Introduction to Selling on OpenSea

Trading on OpenSea is a trust-minimized process.  In other words, you don’t have to trust OpenSea or your counterparty to behave honorably.  You can buy and sell without fear, relying on technology instead of reputation to ensure that things turn out right.  The technology we use allows users to buy and sell digital assets directly with their peers, all without relying on escrow or trusted third party payment processors.

On OpenSea, deals are atomic. That is, either the whole deal happens or none of it does.  In short, OpenSea allows strangers to say to one another, “if you do that, I’ll do this” without worrying about who should go first.  


A handoff should not be so painful.

On eBay, you have to pay the seller before they ship the goods.  On OpenSea, the seller makes a binding promise to sell goods for a certain price, the buyer makes a binding promise to pay the price, and when those two promises are paired up with one another, the deal happens in a single transaction.  Things almost always go well, but when they don’t, it’s like the deal never started.  No one’s left empty handed.

To make these features possible, each user must do a little bit of initial setup before making his or her first listing. The first transaction creates your proxy account, which is a tiny little smart contract that only you can use.  It allows you to interact with the Wyvern Protocol.

The Wyvern Protocol is an audited, battle tested, and secure suite of smart contracts that enables its users to swap state changes on the Ethereum network.  At OpenSea, we use it to help users trade NFT ownership state for cryptocurrency ownership state.  More simply put, we use it to facilitate NFT sales.

The second setup transaction authorizes your proxy account to move a given type of NFT on your behalf, so when the NFT sells, it can be transferred to the buyer instantly.  Both of these transactions are free, except for the gas that the Ethereum network requires. 

Depending on the currency you’re using, you might need to do a third transaction that authorizes the Wyvern Token Transfer Proxy to move ERC20 tokens on your behalf.  But don’t worry, unless you sign an order, Wyvern can’t move any assets.  Wyvern has moved tens of millions of dollars worth of value and no one has yet found a vulnerability that would allow them to take tokens that don’t belong to them.

After you complete these two or three initial steps, you’ll only need to sign a message with your wallet to create a new listing. And it won’t cost any gas at all. If you’re getting curious about gas by now, here’s that link to the writeup about gas again.  If not, no sweat, I played around with Ethereum for months before I took the time to really understand gas and never suffered negative consequences as a result.

Now, armed with at least a baseline knowledge of why OpenSea behaves as it does, let’s talk about how to create listings.

Creating Listings

OpenSea allows you to create a few different types of listings.  Each one serves a different purpose and has a different behavior.  Let’s take a look at the three options.

English auction – This is the type of auction that usually first comes to mind when you hear the word “auction.”  A seller offers an item for sale at a minimum price and awaits bids. After a duration, the seller accepts the highest bid. It’s the type of auction made popular by eBay.  It’s commonly associated with speed-talking, hammer-wielding auctioneers. Check out our co-founder Alex’s article on English auctions if you’re curious to learn more.

Dutch auction – The Dutch auction doesn’t enjoy such a prime position in the public imagination.  It was born as a solution to the problem of chaotic 17th century Dutch flower auctions and hasn’t seen a lot of use outside of certain esoteric marketplaces since. Unexpectedly enough, a quirk of Ethereum’s limitations gave it an unexpected renaissance in the early days of the non-fungible token market. A seller starts by offering the item for sale at an improbably high price and gradually lowers the price as time passes. When the price reaches a level equal to a buyer’s valuation of the goods, the buyer can purchase the item and receive it almost instantly. 

Fixed Price – A traditional “buy it now” transaction. Sellers list an item for one price. The price never changes. Buyers can purchase at any time.  It’s like what you encounter on Amazon.

Whichever type of listing you want to create, the process starts out the same.  Go to your account page and click on the item you want to sell.  Then, click the blue “Sell” button.

You’ll be redirected to a page where you can configure your listing. 

In this case, I’m going to create a Dutch auction.  I’ll set the starting price to 0.1 ETH, toggle the “Include ending price” switch, set an ending price of 0.001 (the lowest price I’m willing to accept), and select the “1 month” option from the “Set expiration date” dropdown.  Over the course of the next month, the price will gradually decline.  With any luck, the price will cross through a range that a buyer finds attractive.  When that happens, the buyer purchases the item and the funds are exchanged for the goods in a single transaction.  But I’m counting my chickens before they’re hatched.  I still need to finish the listing.

When I click the “Post your listing” button, I’ll see a highlighted window appear on the page and I’ll get a popup from my wallet.  Here’s what it looks like for me.

If it’s your first time selling something on OpenSea, you’ll get a few popups asking you to complete a few initialization transactions.  And the first time you create a listing for an item from a new collection, you’ll have to do a transaction.  The transactions will require a few cents worth of gas a piece.  But if you’ve done this kind of thing before, you’ll only need to sign a single message, which is instant and free.

When I’ve completed all the necessary steps with my wallet, I see a page that looks like this: 

Now, when I visit the page for the item I just listed, I’ll see a few new options.  I can reduce the price, cancel the listing, or add another listing using the new buttons.  Adding a new listing if you want to auction the item and offer a buy-it-now price simultaneously.

But when someone else visits the page, they’ll see the “Buy” button.  Pro tip: if you want to check on your listing from a different account and you’re using MetaMask, you can click the MetaMask icon in your toolbar, then click the colorful circular icon in the top right corner of the MetaMask window to switch between accounts.

Bundles

Most users buy and sell single items most of the time, but as Jim Barksdale asserts, there are “only two ways to make money in business: One is to bundle; the other is unbundle.”  So, for the sake of not leaving money on the table, let’s take a look at the process for listing two items, together, in a bundle

You can access the bundling page from anywhere on the site by hovering over the “Account” option in the navigation menu, then selecting “Sell a Bundle” from the dropdown list.  On the bundling page, you’ll see a list of your assets.  I’m going to select two Dragonereum items.

You can bundle up to 30 items in a single listing.  Why only 30?  It comes back to gas again.  By design, a single Ethereum block can only do so much work changing on chain state.  That limit is known as the block gas limit.  In short, transferring more than 30 items requires more gas than a single block contains.  And if you can’t do the whole deal in a single block, you can’t do it in a single transaction.  If you can’t do it in a single transaction, you can’t do it in a meaningfully trust-minimized way.  Here at OpenSea, we value trust minimization, so for now, we’ll all have to live with bundles of 30 items or fewer.

Back to business. Next, I’ll scroll down to the bottom of the bundling page, add a title and description, then set the price for the bundle. 

In this same bundle configuration section, you can set an ending price and an expiration date.  Adding values to these fields will convert your listing from a fixed price listing into a Dutch auction like the one I made above.

By default, your listing will be available to anyone who wants to buy it, but you can make a listing private by toggling the privacy switch and specifying the address that’s eligible to purchase it.  If you create a private listing, it’ll still be visible to everyone, but only the specified address will be able to purchase it.

Finally, I’ll scroll back up to the summary, double check that everything looks right, and click the “post your listing” button. If it’s your first time selling something on OpenSea, you’ll get a few popups asking you to complete some initialization transactions.  But if you’ve done this kind of thing before, you’ll only need to sign a single message.

Once I’ve signed the message, I’ve got a bundle for sale.  When a buyer comes along and purchases your bundle, we’ll handle the transfer of the goods and the funds, just like we do for a listing of a single item.  The funds will appear in your wallet as soon as the purchase transaction is confirmed.  If you’ve set an email on the account settings page, we’ll email you to let you know the good news.  

That’s It!

We’ve covered wallets, browsing, buying, bidding, and selling.  Armed with this knowledge, you should be well prepared to join the world of NFT collecting.  If you run into any issues or have any further questions, please let me know!  I love chatting on Discord.  I’m the bald smiley face with glasses:

If you contact me and let me know you found me through this article, after I’ve answered all your questions, I’ll send you a souvenir item.

Please share your listings in our #trades channel on Discord.  And be sure to mention me whenever you tweet links to your listings.  I’ll retweet listings that use the hashtag #OpenSeaIsEasy.
Thanks for joining us.  Welcome to the world of NFTs! 

-Dan from OpenSea

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