In this Tutorial, We’ll go through the process of building the smart contracts that hold the business logic for our NFT marketplace.Step 1: Cloning the Tutorial Repo1.1 Forking the Tutorial Repository:<ul><li>Head over to our <a href="https://github.com/BuildBearLabs/Tutorials">Tutorial Repository</a> and click on the “Fork” button to create a copy of the repository on your own account. Wait for the forking process to finish before proceeding.</li></ul>1.2 Cloning the repository locally:<ul><li>Go to your forked repository on GitHub.</li><li>Click the “Code” button and copy the HTTPS or SSH URL.</li><li>Open your terminal or Git Bash.</li><li>Navigate to the directory where you want to clone the repository.</li><li>Run the below command to clone the Repo.</li></ul><pre><code class="language-plaintext">git clone &lt;paste the URL you copied&gt;</code></pre><ul><li>Wait for the cloning process to complete. Once it’s done, you should see a new directory with the name of the repository in the directory.</li><li>To move into the cloned repository, use this command<code>cd &lt;Name of the cloned Repo&gt;</code> , then move to the nftmarketplace folder using this command<code>cd nftmarketplace</code> .</li></ul>Step 2: Developing the smart contract<figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*CwKzO-Kq9boo12bn3M-_JQ.png" alt="" loading="lazy"></figure>There’s a lot to unpack here! You might notice that the Marketplace contract inherits <code>ReentrancyGuard</code>. We do this so that we can defend against reentrancy attacks.First, let’s dive into the contract variables:<ul><li><code>Counters.Counter private _nftsSold</code> increments when a NFT is sold and decremented when a NFT is relisted.</li><li><code>Counters.Counter private _nftCount</code> tracks how many NFTs have been listed.</li><li><code>uint256 public LISTING_FEE</code> is taken from the seller and transferred to the marketplace contract owner whenever an NFT is sold.</li><li><code>address payable private _marketOwner</code> stores the Marketplace contract owner, so that we know who to pay the listing fee to.</li><li><code>mapping(uint256 =&gt; NFT) private _idToNFT</code> associates the unique tokenId to a the NFT struct.</li><li><code>struct NFT</code> stores relevant information for an NFT listed in the marketplace.</li><li><code>event NFTListed</code> is emitted every time a NFT is listed.</li><li><code>event NFTSold</code> is emitted every time a NFT is sold.</li></ul>Next, we’ll go over the functions that will alter state:<ul><li><code>listNft</code> is called when a user first mints and lists their NFT. It transfers ownership from the user over to the Marketplace contract.</li><li><code>resellNft</code> allows users to sell an NFT that they purchase on the marketplace.</li><li><code>buyNft</code> is called when a user buys an NFT. The buyer becomes the new owner of the NFT, the token is transferred from the owner to the buyer, and the listing fee is given to the marketplace owner.</li></ul>Finally, the query functions are relatively straightforward:<ul><li><code>getListedNfts</code> retrieves the NFTs that are currently listed for sale.</li><li><code>getMyNfts</code> retrieves the NFTs the user has bought.</li><li><code>getMyListedNfts</code> retrieves the NFTs the user has listed for sale.</li></ul>We will also be using a <a href="https://github.com/BuildBearLabs/Tutorials/blob/main/NFTMarketplace/contracts/BasicNFT.sol">Basic NFT</a> smart contract for testing the <a href="https://github.com/BuildBearLabs/Tutorials/blob/main/NFTMarketplace/contracts/Marketplace.sol">NFT marketplace</a>, available in the contracts folder.<h1 style="margin-left:0px;">Step 3: Getting up the infra needed to deploy and test our smart contract</h1>3.1. Visit the <a href="https://buildbear.io/">BuildBear App</a> (why BuildBear: Read article <a href="https://medium.com/@thomas_90087/a-thank-you-to-buildbear-5873b8394da5">here</a>).3.2. Create your Private Testnet forking from the Ethereum Mainnet, feel free to fork any Chain.<figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*2M9wY3bsj3uWxAX_sFSi4Q.png" alt="" loading="lazy"></figure>3.3. Add your Private Testnet to your MetaMask wallet by using the “Add to Metamask” button:<figure class="image image_resized" style="width:601.99px;"><img src="https://miro.medium.com/v2/resize:fit:506/1*hhrVwlwyI22XrK1303-CDw.png" alt="" loading="lazy"></figure><h1 style="margin-left:0px;">Step 4: Deploying the Smart Contract</h1>For installing the necessary packages, please execute the following command.<pre><code class="language-javascript">npm install</code></pre>4.1 Update the<code>hardhat.config.js</code> .<ul><li>Head to your Dashboard and click on “verify contract”.</li></ul><figure class="image image_resized" style="width:617.987px;"><img src="https://miro.medium.com/v2/resize:fit:519/1*dclMYtIErTLTCPr2yzgI4A.png" alt="" loading="lazy"></figure><figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*sKH90uducy-KiB9KrQXO-w.png" alt="" loading="lazy"></figure><ul><li>Copy the BuildBear and Etherscan objects, and update the <a href="https://github.com/BuildBearLabs/Tutorials/blob/main/NFTMarketplace/hardhat.config.js"><code>hardhat.config.js</code></a> file.</li></ul>4.2 To deploy the <code>NFTMaeketplace.sol</code> and <code>basicNFT.sol</code>smart contract runs the deploy command. <code>npx hardhat deploy</code> This will run the deployment and verification scripts in <code>deploy/00_deploy_mainContract.js</code>, <code>deploy/00_deploy_basicNft.js</code> and save the deployment details along with ABI and Contract address in the <code>deployments</code> folder.<figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*HW2VsgGzG1ot-Kll6pQqXQ.png" alt="" loading="lazy"></figure><ul><li>Click on the link provided in the terminal to see the Contract on Explore page.</li></ul>WOOT WOOT 🎉 🎉4.3 Mint and listing an NFT on the marketplace.<figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*4tbCpSpUgwyDWsTJUDqWmg.png" alt="" loading="lazy"></figure>The scripts for Mint a basic NFT and listing the NFT on the Marketplace have already been configured in the <a href="https://github.com/BuildBearLabs/Tutorials/blob/main/NFTMarketplace/scripts/mintAndListNFT.js"><code>scripts/mintAndListNFT.js</code></a> file, as demonstrated above. To execute the scripts, please run the following command.<pre><code class="language-javascript">npx hardhat run scripts/mintAndListNFT.js</code></pre><figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*KaVvCW7qtPOGQLCVA9-ihw.png" alt="" loading="lazy"></figure>NFT has been successfully minted and is listed on the NFT Market Place.4.4 Buying the listed NFT<figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*J1qq6KMXDp9OkMhRJoWWlQ.png" alt="" loading="lazy"></figure>The scripts for Buying an NFT on the Marketplace have already been configured in the <a href="https://github.com/BuildBearLabs/Tutorials/blob/main/NFTMarketplace/scripts/buyNFT.js"><code>scripts/buyNFT.js</code></a> file, as demonstrated above. To execute the scripts, please run the following command.<pre><code class="language-javascript">npx hardhat run scripts/buyNFT.js</code></pre><figure class="image image_resized" style="width:679.985px;"><img src="https://miro.medium.com/v2/resize:fit:588/1*r00NAQjx0YYw3VG23fqiag.png" alt="" loading="lazy"></figure>We have successfully brought the NFT.We have successfully built an NFT Marketplace, deployed it, Listed an NFT, and brought it through another account !!! 🎉🎉🎉Share your project on Twitter and LinkedIn and tag BuildBear.If you appreciate what we are doing, please follow us on <a href="https://twitter.com/_BuildBear">Twitter</a>, and <a href="https://www.linkedin.com/company/build-bear/">LinkedIn</a> and <a href="https://t.me/+6mjOnBFUR9xjN2U1">Join the Telegram</a> group if you haven’t done yet.And please give us a clap 👏 if you like our work.Github Repo : <a href="https://github.com/BuildBearLabs/Tutorials">Buildbear Tutorials</a>About BuildBear:BuildBear is a platform for testing dApps at scale, for teams. It provides users with their own private Testnet to test their smart contracts and dApps, which can be forked from any EVM chain. It also provides a Faucet, Explorer, and RPC for testing purposes.<blockquote>BuildBear aims to build an ecosystem of tools for testing dApps at scale for the teams.</blockquote>

Building a Decentralized NFT Marketplace with Solidity and Hardhat: A Step-by-Step Tutorial

Let’s get started then, Shall we?

Let’s get started then, Shall we?

Test DApps at Scale.