What is OpenSea, how to create and sell NFT tokens on the marketplace


OpenSea is a marketplace that allows creating, selling and buying NFT tokens. As of early 2022, the platform holds the global leadership in the market for non-interchangeable tokens: in January 2022, the monthly trading volume on the platform reached the $3.5 billion mark and broke its August record of $3.42 billion.

What makes Open Sea such an attractive platform is the ease of operation: finding, creating, selling, or buying the desired token is very easy here. The creators of the platform specifically focused on the usability of the service, so you will hardly find any negative user feedback about OpenSea.

In addition to recognition among users, the investment in friendliness has also brought quite tangible benefits. In 2021, the marketplace accounted for 88% of global NFT trading volume, and in early January 2022 it attracted $300 million in investments from the Coatue and Paradigm crypto venture capital funds. After that, OpenSea’s valuation reached $13.3 billion.

But just being friendly with users is not enough to become “number 1 in the NFT market”. To understand the success of OpenSea, cryptonisation.com editorial staff invites you to dive into the project’s history – look at it from 2017, when everything was just starting and success was not so evident. 🚩

History of OpenSea development

In 2017, OpenSea founders Devin Finzer and Alex Atalla were involved in the Wificoin project at the Y Combinator venture fund. However, sensing the prospects of NFT, already being part of the gas pedal, they decided to change the direction of the company, and began to develop Open Sea. It was a very risky move – NFT was still in its infancy, and few people believed in its prospects. But it was not only Davin and Alex who found the idea promising. At the same time, OpenSea’s main competitor, Rare Bits, appeared.

After the growth stage at Y Combinator, OpenSea managed to raise $2 million for development, while Rare Bits raised $6 million – competitors outpaced Open Sea at the start. But in 2018, OpenSea beat its rival. 🔥

OpenSea, like many similar services, drew inspiration from CryptoKitties, an online game released in 2017 that used non-interchangeable tokens on the Ethereum standard ERC-721.

In CryptoKitties you had to breed and cross cats that looked like two-dimensional pictures. The unique pictures obtained after “crossing” could be bought and sold.

Rare Bits reimbursed users for network fees and waived fees for some transactions altogether, while OpenSea simply charged 1% on all transactions. This helped OpenSea get through 2018, a tough time for the crypto industry. In addition, Finzer and Atallah were literally living the marketplace, looking for new NFT projects, and pretty quickly outperformed Rare Bits in terms of trading volume.

In the end, OpenSea’s reliance on longevity, leisurely replenishment of the catalog, and refinement of the buying and selling functionality did the trick: in 2019, Rare Bits went into hibernation. The competitor had fallen, and OpenSea was just gaining momentum.

OpenSea creators

Devin Finzer and Alex Atalla didn’t come to the crypto community out of nowhere – both had serious development experience. Devin wrote CourseKick back in 2011 while at Brown University. It allowed students to remotely enroll in additional courses and see which ones their friends had chosen.

After Finzer worked at Pinterest, then developed Iris Labs vision test sheets and the financial app Claimdog.

Blockchain came into Devin’s life in 2017. That’s when Finzer met Alex. Attala studied computer science at Stanford. During his studies he also developed small social networks for student needs, and after graduation he worked for several years as a technical director at a startup.

Register at OpenSea.io

How to register at OpenSea.io

You can sign up for OpenSea by connecting a digital wallet to the marketplace. By default, the platform offers to use Metamask crypto-purse, but there is an opportunity to choose other options.

Supported wallets.

Open Sea supports the following wallets:

  • Metamask;
  • Coinbase;
  • Walletconnect;
  • Fortmatic;
  • Kaikas;
  • Bitski;
  • Venly;
  • Dapper;
  • Authereum;
  • Torus;
  • Portis;
  • Opera Touch (mobile version only);
  • Trust Wallet (mobile version only).

How to buy NFT on OpenSea

To buy an NFT token, just go to your OpenSea account, find the token you are interested in and buy it 😁. To make sure you don’t get lost along the way, we’ve prepared a little step-by-step guide on how to buy tokens.

A step-by-step guide

The buying process step by step:

  1. Go to 👉 OpenSea.io;
  2. Create an account by connecting a digital wallet to the site, or log in to an existing account;
  3. Add ETH to the selected wallet (if you connected only one wallet, it will be the only one in the list). The platform allows you to transfer ERC-20 standard cryptocurrency from another wallet/exchange or buy it with a debit card;
  4. Find the NFT we want to buy, click on its image or name;
  5. A window opens with information about the NFT, statistics, and previous owners;
  6. To buy a token, click Place Bid or Buy Now;
  7. In the form that opens, you will need to enter the amount of payment or set the value of the bet. You will also need to accept the terms of the platform by clicking on the checkbox;
  8. Next, the system will redirect you to the wallet, where you will need to confirm the transaction by entering your personal key or the original phrase. At this stage you can still cancel the payment;
  9. After confirming the transaction, OpenSea will display the NFTs you purchased in your account dashboard.

The platform user can buy an NFT token in two ways: using the Place Bid command (if buying an object at an auction) or Buy Now (if buying at a fixed price). In the latter case, the buyer can offer the seller his price by clicking on the Make Offer button. The duration of such an offer can be set in a separate dialog box.

Creating a token collection at Opensea.io

Marketplace allows you to create collections of tokens. A collection is simply a directory-folder that contains tokens with some common attribute. For example, avatar pictures of one series. Sellers can combine tokens into collections 👍 so that buyers can easily navigate through them, buyers – to keep their token collection in order.

What you need to build a collection

To create a collection, log into your account ⟶ move the pointer to your avatar ⟶ and select My Collections from the drop-down menu.

In the window that opens, click Create the collection and design the collection. You will need:

  • Logo image – image, 350×350 px;
  • Featured image – will be used to display the collection on OpenSea pages, 600×400 px;
  • Banner image / Cover banner – to show your collection on the pages of OpenSea, 1400×400 px;
  • Name / Name of the collection;
  • URL – in this field you can customize the url-link that will be used to find the collection;
  • Description – up to 1000 characters;
  • Category – allows you to add a collection to the categories presented on the Marketplace;
  • Links – this field allows you to add links;
  • Royalties / Remuneration – the field allows you to set the percentage of the remuneration for all subsequent resales of tokens of the collection. The maximum is 10%;
  • Select the token placement blockchain (Blockchain) and the types of tokens that can be used to pay for the collection items (Payment tokens);
  • Select the proposed display option for the collection in the user panel and the platform’s search engine;
  • Click Create.

After creating a collection, the platform redirects you to the collection page. To add a new object to the collection, click Add Item in the upper-right corner of the screen. If you already have items created, the system will redirect you to their list. If there are no created tokens, it prompts you to create the first item in the collection.

Creating an NFT token on OpenSea

You can create an NFT token on OpenSea in two ways:

  • As an individual item by clicking the Create button in the upper right corner of the screen (you will be able to add the token to the collection when you create it);
  • As an item in an existing collection by clicking the Add Item button on the collection page.

In the first case, the token must be added to the collection separately; in the second case, the item will be added to the collection immediately. However, the steps to follow when creating a token are the same for both cases:

  • Go to the token creation page by selecting one of the above options;
  • Choose which object we want to turn into a token. You can use an image, video, audio or 3D model. The maximum size is 100 MB.Acceptable file formats: jpg, png, gif, svg, mp4, webm, mp3, wav, ogg, glb, gltf..;
  • Write the name of the token in the Name field;
  • Then the external link in the External link / External link (for example, to your site);
  • In the Description field, set the description of the token;
  • In the Collection drop-down box, you can add the token you want to create to an existing collection;
  • Next are the modules that you can add to the page of the created token (Properties, Stats, Levels), a checkbox to enable visibility of the additional item field (Unlockable Content), a checkbox to mark the token as Explicit & Sensitive Content, and a checkbox to mark it as Explicit & Sensitive Content;
  • Supply – determines the number of tokens that will be mined. For now, this number on OpenSea is limited to one 🙁;
  • Blockchain – select the blockchain on which the token will be created;
  • Once all the checkboxes are configured and the fields are filled in, click Create – your NTF token is ready.

What is minting? Minting is one of the ways to get remuneration in the form of cryptocurrency. The essence of minting is the creation of new blocks (in application to the subject of NFT – new NFT-tokens) on the blockchain and receiving a reward in the form of a percentage of the block value 📈.

Publishing NFT

Publishing an NFT ad for sale

To publish NFT token ads on OpenSea, you need to:

  • Log in to your account;
  • Select the token you want to put up for sale;
  • Go to the token page and click the Sell button in the upper right corner;
  • In the browser window will open a page with the conditions of sale setting.

The platform provides the following options:

  • The ability to sell a token at a fixed price – Fixed Price. This option also has a Bundle feature, which allows you to sell multiple tokens;
  • The ability to sell a token at a timed auction – Timed Auction.

How to sell NFTs

Consider all options for sale at Opensea in more detail.

Fixed Price

The easiest option is fixed-price sales.

The seller only needs to set the cost in the Amount / Quantity field and specify the duration of the sale activity in the Duration field.

If you click the More Options checkbox in the sales condition setting window, you will find two more options:

  • Reserve for specific buyer – allows you to sell your token to a pre-selected buyer;
  • Bundle – this feature is worthy of special mention.


This is a selling method that allows you to bundle several tokens together and sell them as a whole 💰. Up to 30 tokens can be combined into such a bundle. To add a token to the bundle, you need to activate the checkbox Bundle in one of them, and then add the desired tokens from the drop-down list.

Timed Auction

A time-limited auction. OpenSea offers two ways to work with it:

  • Sell to highest bidder is a classic fixed duration auction. It is sold at the highest bidder. The additional function Include reserve price allows you to set a reserve price at which the token will be offered, if no one outbids the seller during the auction;
  • Sell with declining price is a fixed duration “reverse” auction. Seller sets a starting price and a minimum ending price. The price decreases gradually from the high starting price to the allowed minimum price. A token is sold to the first person to pay the current auction price.

What commissions will have to be paid when selling the token

Like any marketplace, OpenSea charges a transaction fee.

The platform team is trying to optimize the amount of commission and unify the stages at which it is charged. 👇

Token sales commission

OpenSea charges 2.5% for any transactions within the system. But you should also keep in mind the transaction fee for the Ethereum blockchain.

Commission for creating a smart contract on OpenSea

The marketplace does not charge a fee for creating a smart contract. All NFT tokens are created free of charge and at any time.

OpenSea mobile app

In September 2021, OpenSea launched a mobile version of the marketplace as an app for iOS and Android. However, it works like a gallery: you can fully use the user’s cabinet, view NFT items on the platform, but there is no possibility to buy and sell tokens.

Referral program

OpenSea recently offered users to participate in a referral program. All you had to do was add a unique identifier to the external links to your tokens – and you could receive up to 2.5% extra reward on each purchase.

Although there is still a mention of the referral rewards program in the user manual, this functionality has either been removed or is being redesigned at this time.

Pros and cons of the OpenSea Marketplace

The largest marketplace in the world: 88% of NFT trading volume takes place on OpenSea;

Convenient, safe and user-friendly service;

Easily create, buy and sell NFTs;

Low commissions, no hidden fees.

The site does not rush with innovations, focusing on the development of existing functions of the service. In the long run, this may lead to a lag in functionality and capabilities.

A mobile app that works only in gallery mode;

Only three blockchains are supported: Ethereum, Polygon, Klaytn.


What is OpenSea?

The world’s largest marketplace for creating and trading NFTs.

How to create an NFT on OpenSea?

You need to click on the main page Create and follow the instructions.

How do I buy an NFT on OpenSea?

You need to select the token you like, click on it and click Place Bid or Buy Now. Then confirm the transaction in the wallet.

How to sell NFT on OpenSea?

Select the token you want to sell, click on it, and click Sell on the token page. Then select the type of sale, assign a value and click Complete listing.

What are the commissions on OpenSea?

OpenC takes a 2.5% commission on each transaction.

How to transfer an NFT token from Open Sea?

Go to Opensea, select the NFT to be transferred, click the “Transfer” icon on the NFT-token page and enter the desired address in the window that appears.


OpenSea is a convenient and secure platform that allows you to trade and create NFT tokens. To start using the service, you just need to connect a digital wallet.

The platform allows you to sell NFTs at fixed prices and through auction, has many additional features, such as the ability to sell NFTs, combining them into bundles.

Opensea takes 2.5% commission on every transaction within the system, but don’t forget about Ethereum network commissions, which can be high. Unfortunately, there is no full-fledged trading via mobile app yet, which works only as a gallery.

In 2022, the marketplace promises to increase the speed of system development, launch a grant program to support NFT creators, and continue developing existing services. These changes could cement Opensea’s position as the largest platform for NFT creation and trading.