With all the hype and trends around NFTs, crypto, and Metaverse, I figured I'd rather be part of the movement than scratch my head over all the memes. Today I'll share my experience building an NFT on the Polygon blockchain on Opensea.

What is an NFT?

Before we talk about building an NFT, let's first define what it is. Wikipedia's definition is as follows:

A non-fungible token is a non-interchangeable unit of data stored on a blockchain, a form of digital ledger. Types of NFT data units may be associated with digital files such as photos, videos, and audio. Because each token is uniquely identifiable, NFTs differ from blockchain cryptocurrencies, such as Bitcoin.

Ok, now I'm even more confused.

I surfed around the web to understand NFTs in a simpler way and came to the conclusion that NFTs are just digital assets that hold value, just like how physical art holds value. What makes NFTs special is that behind every NFT artwork, there is a unique and unchanging piece of data stored on a blockchain like Ethereum.

NFTs are caving a new, unique way for artists to creatively express themselves and for people to build upon new forms of ownership.

Now that we have some understanding of what NFTs are, let's dive right into how to build one.

Step 1: Prepare an Awesome Artwork

NFTs can be any image, video, audio, or 3D model, anywhere between a tweet and an amazing artwork. I decided to mint a pixel art my lovely girlfriend made for me on Figma.

Figma is a free, easy-to-use tool that many artists and designers use regularly, and if you don't have experience with design, I suggest you take 45 minutes to learn the basics of Figma.

Step 2.1: Make a MetaMask Account

In order to register for Opensea, you first need a crypto wallet. There's a variety of wallets you can use, but I chose MetaMask for being compatible with most dApps (decentralized applications) on the Ethereum ecosystem.

MetaMask works as a chrome extension, so it's really convenient to use whenever you make a transaction or login to a dApp project. You can also download it on iOS or Android, but the chrome extension is sufficient for most use cases. Side note: Opensea is also available on iOS and Android, but you can't buy or sell NFTs on a mobile app.

Make sure to note down your Secret Recovery Phrase to prevent being locked out of your account!

Step 2.2: Add Polygon to MetaMask

Due to the Ethereum blockchain's current proof-of-work mining mechanism and the high traffic it receives, minting an NFT on the Ethereum network comes with expensive gas fees.

To solve this issue, three software engineers in India developed Polygon (formerly MATIC Network), a layer-2 scalable solution built on top of the Ethereum blockchain. Polygon is very efficient and has low gas fees associated with transactions. On Opensea, you can mint an NFT on Polygon blockchain for free!

Polygon Tradeoffs

Not paying any gas fees sounds awesome. But like many things that are awesome, Polygon comes with some tradeoffs. I suggest you watch Aprilynne Alter's deeper dive on the comparison on her YouTube channel.

1. Opensea does not allow auctions for Polygon. You can only set fixed prices for your NFTs.
2. Polygon tends to be less secure than Ethereum because it's more centralized. It's also what makes Polygon more scalable.
3. Buyers are less familiar with Polygon. Some NFT collectors may be reluctant to buy NFTs on Polygon.

It's up to you to make the judgment, but a good rule of thumb is to choose Polygon for high frequency, low-value NFTs and to go with Ethereum for low frequency, high-value NFTs.

Configure Polygon Network to MetaMask

To add Polygon to your MetaMask, start up the MetaMask chrome extension and click "Add Network" on the dropdown menu that indicates "Ethereum Network". Enter the Polygon Network configuration as follows:

• Network Name: Matic Mainnet
• New RPC URL: https://rpc-mainnet.maticvigil.com/
• Chain ID: 137
• Currency Symbol: MATIC
• Block Explorer URL: https://explorer.matic.network/

Click "Save", and now you've successfully added Polygon on MetaMask! To use Polygon network, select "Matic Mainnet" from the network dropdown menu.

Step 3: Setup Opensea Profile

This is super simple. There's no need to sign up with a username and password. On Opensea's website, connect to the MetaMask wallet you just created and update basic profile information.

Step 4: Mint your NFT

Click "Create" in the top right corner of the site, add your artwork, and provide all required information.

Now, the important part: the default blockchain is Ethereum. Change it to Polygon.

Click "Create" once you're done, and congrats! You've minted your first NFT! If this was helpful, follow me on Github @ madebybk to stay up to date on all my projects.