How to create a free NFT to sell on OpenSea

As infamous as they are popular, the non-fungible tokens, or simply “NFTs”, have become a fixed topic in social media debates. The articles are digital certificates, authenticated and stored on a blockchain, which guarantees their integrity and transparency for all interested users. Although its use can be quite varied, extending to residential contracts, its popularization took place through digital art auctions.

However, little is said about the steps for creating an NFT, something that contributed to the fallacy that the process would be complex and inaccessible. To demystify this doubt, the TecMundo prepared a guide to help more inexperienced users who are interested in the technology. Check out!


Before starting, it is important to point out some basic requirements to carry out the process. Considering that the user has already defined a media to be mintada (term derived from “mint”, something like “minting” in Portuguese), there will only be:

  1. Choose a platform
  2. Set a preferred blockchain
  3. Own a cryptocurrency wallet that supports the chosen platform
  4. Possess some cryptocurrency balance to fund the process if it is carried out in Ethereum. In this case, we will use the Polygon blockchain, which allows us to create the NFT free of charge, but fees will be charged at OpenSea if the sale is made.

Installing a cryptocurrency wallet

A crypto wallet is a digital address capable of holding both cryptocurrencies and tokens or NFTs. Although many alternatives are accepted by niche services, the MetaMask is often the top choice among users.

MetaMask digital wallet interface. Fonte:  MetaMask

To use it, just access its official website and download it on one of the supported platforms: Android, iOS and web browsers — including Chrome, Edge, Firefox and Brave. After installation, just create a MetaMask account and proceed to the next step.

choosing the platform

If the user’s ultimate goal is to sale of NFTsyou should choose the platform based on your liquidity and number of active users. Within these criteria, the highlights are for OpenSea, Rarible e Foundation, that are popular and have a desirable level of support for updates and features.

Considering these factors, the tutorial will use the OpenSea as an example, the most famous in the niche — in it, there is a 2.5% usage fee per transaction performed and support for different blockchains. However, it is worth mentioning that the process is similar in the other alternatives.

Predominant in the last year, OpenSea already faces strong competition from LooksRare. Predominant in the last year, OpenSea already faces strong competition from LooksRare. Fonte:  The Block

Alternatively, a good practice for users who want to try out competing platforms is to check out the fees charged and features offered, as this will influence the rest of the sales process.

Creating an NFT in Open Sea

Before creating an NFT on OpenSea, it is necessary to “register” on your trading platform. The process is simple and only requires authorization from the user’s cryptocurrency wallet, which will be used to provide the funds used in transactions and to store the purchased works.

1- Registering an account on the trading platform

To register, simply click on the profile icon, located in the upper right corner of the home page. Next, select a preferred wallet and authorize access. Check out the step by step in the images below:

Adriano Camanho/ReproductionSteps for creating an account on the OpenSea platform.

The user will be able to customize their profile on the platform with personal information, photos and presentation banners, as well as a display name and link to their social networks.

2- Creating a Collection of NFTs

After registering, the next step is to create a NFT collection, whether thematic or not. To get started, simply hover your mouse cursor over the Profile icon and select “My Collections”, then “Create a Collection”.

The process is similar to creating a profile on a social network, with the main difference being in the final steps. It must define a commission percentage for the creator under each transaction that refers to the collection — including the purchase and resale of items. In addition, it is also necessary to inform on which blockchain the trades will be carried out, as well as the types of cryptocurrencies accepted.

In short, it is possible to choose the networks Ethereum e Polygon at OpenSea. The first is widely used by users, but requires an operation rate that can be high and unfeasible — known as “Gas Fee”.

On the other hand, the Polygon it’s free and fast, but it still doesn’t have a big adoption margin and could affect the speed of sales. After all, if the token is mined on the Polygon blockchain, it can only be sold to Polygon users.

See the step by step in the images below:

Adriano Camanho/ReproductionSteps of creating a Collection of NFTs.

3- Publishing an NFT

With all the requirements completed, it is possible to publish an NFT. To do this, click on shortcut “Create”, located in the upper right corner of the interface. The next screen is very similar to the one found in the previous topic, but simplified.

In it, you must define which item or set of items will be published, along with a title, external link and description. Going forward, it is necessary to select the Collection that the publication will be destined to, along with some special and optional properties – such as statistics, progress bars and unlockable content for buyers. These adjustments can be made intuitively and have detailed descriptions to assist the user.

To finish, just select the amount of available items, the target blockchain and click “Create”. At the end of the process, the user will have access to a statistics page about the published NFT, also allowing its listing for sale. If you wish to carry out it, you must select the “Sell” option, set a price in a preferred cryptocurrency and authorize the transaction in the digital wallet.

See the process in the images below:

  sale of an NFTPublication and listing for sale of an NFT.

4- Result

As a result, the user will have access to their NFT and purchase offers. To help the process, it is recommended to publicize the item through social networks and online publications. Check out the example, in practice, through this link.

NFT Test listed on OpenSea. NFT Test listed on OpenSea. Source: Adriano Camacho, OpenSea

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