Learn to create and sell your own NFT using Solidity

1. Course Introduction: And if these are on trend right now, everyone is looking to buy a unique and profitable NFP. And creators and developers all around the world are taking advantage of this opportunity. A non-fungible tokens means that it is a unique token that has no other token like it. This is different from the ERC throwing these, which are fungible. Fungible means replaceable, are interchangeable. Nft is bringing Blockchain into the public eye. Now is an excellent opportunity to understand the hype yourself by publishing your own NFT on the Akkadian blockchain. In this course, we will learn to create and deploy and ERC 721 smart contract on their rink a bit test network using MetaMask, solidity, hardhat, Grenada, and alchemy. We will do everything from scratch so that you can understand all the necessary concepts precisely. From setting up a new project, deploying your smart contract, maintain our NFT, and then finally, listing it for cell in a benzene marketplace. At the end of the course, you will have your very first NFT to show off to your friends and in your resume without wasting any more time and roll now and let's get started. 2. What is NFT and its use cases: Hi, welcome to the very first video of this course. So before moving towards the implementation of an NFT, I would like to discuss some 2D part of it as well. So what is an NFT? An NFT is a digital asset that represents real-world objects like music, in-game items and videos. They are bought and sold online frequently with cryptocurrency, and they are generally encoded with the same underlying software as many crypto. So definitely you have heard a lot of hype of this interface. People are buying some, that is the very first tweet as an NFT or some kind of signature, cricket moment, whatever, which is unique. And one of the kind you can make it as an NFT. Nf2 stands for non-fungible token. It's generally built using the same kind of programming as cryptocurrency like Bitcoin or Ethereum. But that's where the similarity ends. That is both NFT or any kind of cryptocurrency. I basically different only the way it's built on a blockchain. That is the similarity. Physical money and cryptocurrencies are fungible, meaning they can be traded on exchange for one another. There are also equal in value. $1 is always worth another $1.1 bitcoin is always equal to another Bitcoin. So that means those fungibility make it a trusted means of conducting a transaction on the blockchain. In simple words, definitely $1 or one rupee can be exchange, but one NFT cannot be exchanged with another NFP. If these are different. Each has a digital signature that makes it impossible for NFV is to be exchanged for or equal to another. Hence, non-fungible. In simple words. Think of what one painting cannot off as an NFT cannot be exchanged to another painting. We can just say like DID, obviously you can buy and sell it. But the basic definition of NFT is this. Okay? Now, now we have understood what is NFT and it is non-fungible. Fungible. What are the NFP use cases? Obviously, there has to be some use cases in order to get so much attention. So few of those Use Cases are number one, gaming. Majority of their games have their virtual currency within the ecosystem that helps users make their progress easier. The different uses of NFT is will allow players to easily trading game collectibles with proper validation or security example, some skin, some kind of sword, fighting, some kind of clothes. These all can be turned into NFP is and can be bought with there any cryptocurrency or that game allowed cryptocurrency. Second is digital asset. For these assets like houseplants, mockups, teams, as well as domains. And it is certainly a perfect match. Moreover, digital real estates in games like the central land is getting popular these days. You can just google these two hinterland and just check it out. You can buy virtual land and trust me, they are very expensive, very expensive. So it's like you can just see how people are using these NFP is, or you can say the blockchain ecosystem. Nowadays, they allow players to purchase and develop a set of spaces in a virtual world. Just like you can sell Nike or any other clothing brand in the Central. And you can conduct events. And a lot, you can conduct a Games, movie halls, movie theaters. Lot of things you can do in that the central land, it isn't my towers. You can see number three. I didn't identity teeth that things that represent identity and can be this, the digitalized, such as medical records and academic qualifications can make use of NFV is to prevent that identity tiff. This makes them a perfect match for issuing certificates, qualifications, and licenses. It helps in separating counterfeits from the original. So obviously, it helps to make sure our habit trust that particular document or that piece of information that it is true. We can use NFT selected. And the fourth one is delta elective words. It's a no-brainer that NF, these are rare and they find their major using collectibles and art. With the addition of this token, the authenticity and ownership of a collectible or an artwork can be easily verified. This allows artists to prevent their work from being misappropriated. Are I edited? And if this has already started to be used in cards and merchandise. So obviously, some kind of painting, some kind of unique art. These all are part of an FTEs and people buy and sell it on different platforms. So that's it. This was a brief introduction to LFTs. In the next upcoming videos, we will learn more about the implementation and how we can build our own NFP as well. Thank you. 3. ERC 721 vs ERC 1155: In this video, we will discuss about that token standards, that is ERC 721 and the ERC 1155. If you search about NFP is these two tokens standards, you will get in the internet. And no doubt we will be using the first one. But at least you should know that difference. The ERC 1155 tokens standard could see much more prominent used in the ER is 721 token standard in the near future. Thanks to its additional features, we will be using ERC 17 t1 in this course, as I said earlier. But both tokens standards have their applications. And it's worth knowing their individual properties to help decide which to implement in your project. Both allow you to maintain new NFS. But there are some key differences such as number one Point. C, 1155 permits the creation of boats, semi fungible tokens, non-fungible tokens, where ERC 721 permits only that letter. That is the non-fungible tokens. So this is the first difference. The second difference is ERC 115 5s. Smart contracts support an infinite number of tokens, whereas years is 721 needs a new smart contract for each type of token. So definitely if your use case, create infinite number of tokens, you have to use the ESC double one, double five tokens standard. That title one is ERC 1155, also allows batch transfer of tokens, which can reduce transaction cost and time. With 721, sending multiple tokens is done individually. So this is another benefit with the ER is C 1155. And the last point here is 1155. Token transfer can be rewarded in the event of a mistake due to its safe transfer function and other rules in place to provide exploitation. On the 721 standard, you can't reclaim assets if they are sent to the wrong address. So this is a very big advantage, I can say. But this will happen. Obviously very rarely dismiss thick, but it can happen. So this keep in mind these differences and also apart from ERCC1 21 gear is another standard called ERC 1155. And if you want, you can google it later on. I may also create course on that as well. In the end, I just have to say, although ERC A11 55 is quickly gaining popularity due to the low gas fee and transition time. Erc 17 different standard will also not be soon forgotten because right now all the NFT is, you see, are returning ERC 721. So this was a very small differences. Obviously, there are a lot of differences between them. I just want you to give a brief overview of it. In the next module, we are going to do the practical portion that is set up our environment and everything. So I would just like you do see the horse roadmap, how we are going to do it step-by-step. First step will be to set up development and harmony with hardhead. Our second step is to create ERC 721 NFT smart contracts using the append Zeplin library. You can see because make sure you know how to use hardhat, you know what is open Zeplin, at least we don't have to remember the code because all the codes are predefined in it. The third thing we will do is create an estimated at that and upload it to IPFS. Are four. Tasks will be deployed as smart contract with the Italian designate using the alchemy portal. Then our fifth tasks will be the mint NFT and view it on our MetaMask wallet. So definitely you have to install on my traumas as well. Our last thing is to list NFT for cell on OpenShift platform. So this is how we will complete this course. You don't have to think too much, but you should know the basics of solidity. Hard hat. What is my Thomas, what is alchemy? At this? These are the basics you have to know in order to continue with that course. That's it for this video. Let's get started working on that code in the next session. Thank you. 4. Install hardhat and its dependencies: Hi. In this session, we will set up that development environment for our project. So just simply go to any directory of your choice and create a folder called my first NFT. Okay? We will be using a tool called hardhead. Hardhat is an environment developers use to test, compile, deploy, and the work decentralized applications based on titanium blockchain. It helps coders and developers to manage many of the tasks that are required to develop depths and smart contracts and make the process easy and fast. So you can just Google it as well. Hardhat. See, this is what I'm talking about. So get started. You can see how this is done. This is the command line which we have to use. The first thing, go inside our folder, that is my first NFT and open up a terminal. You can see it, or you can open up a terminal here on I will just append this folder into VS code. Like this. This. Okay. I am using VS Code if you want, you can use any text editor. Now here, just write new terminal. And then to install hardhat, first, we have to create an empty npm project with this command npm. See, our NPH NPM package is ready. Now we have to use this command to install hardhead as a developer dev dependency. Like npm. Install save dev. I'd had just wait till it executes. You can see here, if you want, you can read this documentation as well. It will help you to understand a lot better. Then. Quick study this, this with this command and px hardhead, we will get a bare bone installation with no plug-ins, but we will get the hardest project in our we will get the folders are the folder structure of a project. So in the same terminal, just simply write that command and px, I'd had press enter. Then you can see this hardhead stuff coming. What do you want to do that is create a basic sample project. We will use this. Press enter, then press Enter, and then press Enter. Like this. See, all these folders and files have been created by a hardhat. And I'm just hoping that you know, the basics of Hardhead because definitely that you must know because they are only two tools, hardhead, all the truffle. These two tools are being used to debug, deploy, test our smart contracts mostly. Now, you can see this line of code, that sample project as us to install all these dependencies as well. Which makes hardhat compatible with tech test. Well with waffle or Chai and ethers library to interact with the smart contract. So simply just copy all this, paste it down here, and press Enter. Let those dependencies installed. Here. You can read about these as well. That is a sample project asked us to install way for terrorists. See you miss, you can stall all of these dependencies. Simply. You have to install these dependencies in order to make it work. That's it. It may take some time. It will just wait and let it finish. See if you don't if you don't know hardhead, you can just read these documentations are simply watch videos on hardhead and then continue with this course so that you don't get confused. But I will say hide it. Hard hat is not a very big deal. You must know solidity, at least. Because hardwired commands, you can just write it down or learn, That's it. Everything is now being installed. You can see the package JSON file, hardhat, eat her GI, dev dependencies. Yeah, everything is now installed properly. In the next video we will work on. That is my Thomas or alchemy. That's it for today. See you in the next video. 5. Alchemy and Metamask account: Hi. In this video, we will learn how to create. We will not learn. You have to create an account in alchemy and MetaMask. So in the previous video, hard hat gives us few folders and file. As you can see, we will understand all those step-by-step. But first let's go to hard hat dot config dot js file. And make sure we, our v are pointing our network to drink to be Italian test network. And for that to work, we need to be itanium node URL, a valid address. So as I already have an account in Alchemy as well as my Tamas. I won't be creating any new account in it. You can just Google it and do it on your own. It's very simple and straight forward. You can just see right alchemy. Here. Click on login. First. I am logging in, but you will get an option to sign up with your Google account. So simply, after you successfully sign up, you will be redirected to this dashboard. You can see here already, I have one app. You won't be seeing this in your dashboard. Simply, our task is to create a new app. I will name it. What? I will just name it. My first NFT, n Here chain will be okay. But the network I will be using rinky. You can see depreciate it, but it is not completely stopped. If later on in the video, if we get any issued, then I will switches to discuss shortly. But right now I am using rink, Maybe. Just click on Create App. See, your app is being created in less than a second. Then in this view key, after clicking, you will get your secret key. Like you can see. This is the STDP URL key. Now the secret key, it is just the alchemy and point. And I will delete this app. So it will be a waste of time for you to try to copy this link. And then next thing you have to do is to get private and public key from your MetaMask wallet. You can install my thalamus by going to my Thomas.io website and install the extension from a four-year browser. I'm not going to set again. It will take, I think five to eight minutes or ten minutes. I guess. You just simply watch a video in the YouTube on how to install and set up my thalamus. Then get back to this course because definitely you will require a MetaMask wallet and also some tests eaters in your account. After installing it, just click on this Madame us. Login to your wallet. Then change the network during COVID test network. Here I have all these, fake it till I got from the faucet. That is rinky be faucet. You can also paste your address and get it for free. Then after here, just study here, click on account details. Export private key, type in your password and you will get a private key. Just copy it. Okay? And public key is this key. That is your account key. This is the public key. Now, we will use this alchemy URL and our my Tamas private and public key in our hardhead configuration, mainly met damask private key. For that, we will install and use a dependency called dot ENV by using that command, npm install. In which just simply write npm install dot ENV. We are using this E and V dot ENV packet because it is not recommended to paste those sensitivity, sensitive keys directly in your code that is hired hardhead configure anywhere directly because it might get pushed to the GitHub by mistake or whatever. Now, this is then go to package.json. You can see this dot ENV being installed. Now in the root directory, create a file called dot e and v. Ok. And now create this variable was alchemy. Url is equal to like this. Then enter. Wallet. Private key is equal to like this. Public key is equal to this. Now, simply go here, copy and paste it here. Then copy. Public, paste it here. And same as export your private key. And paste it here. Let's just save it. Remember there is no comma D and directly and then go to the another line. Now, we have our keys ready. We just have to configure our hardhead to work with those key. In this module that exploit code. Just go down to solidity and write these changes. That is networks. Then it could be. Then URL will be processed. This. But for that to work, you have to require the dot ENV package. It is dot ENV dot config this line of code you have to write in order to make it work. Here we go just says process dot ENV and gamey URL. And second thing yet, right, accounts. Then this square brackets. Within the square bracket, you have to write process that ENV wallet, private key. That's it. Then. Now our project is ready to work with dialing cubit, test net off our alchemy. Thank you. 6. Understanding ERC721 Contract: Hi. Before moving forward, in this video, I would like to talk about the ERC 721 token and spatially the functions and code related to the open Zeplin library. So if you know all the basics and if you know **** NFT minting code, then you can directly skip this video and move forward. Or else just watch this video and understand the small and small details of the ER C7 to T1 contract given us by open Zeplin. For that, I will just simply create a new project because I don't want to do anything with the already NFT project. You don't have to do it. You can just watch it if you want. I'm going to explain the code. And what is the NPM in eight. Then I will simply write npm install hardhead. Then I will simply create a herd ahead project and Px, how great the basic project, that's it. And then I will install open Zeplin slash tracks. Okay, now, open the folder. Okay, now let's go to the pen. That plane website. Here you can see contracts. And then just click on Get started. So we have installed this NPM package. Now click on years is 721. Now here you can see this basic NFT maintaining code we just copied. So here they're using this ERC 17 D1 to track items in their game, which will have their own unique attributes. Whenever one to be awarded Web Player, it must be maintained and sent to them. Okay. So that's it. I will just copy it. Create the file. Yeah, 721, demo dot soda. And basically this is just should be solely the D O k. Now, here we can see the functionalities of an ERC 721 token. Functionalities are transfer tokens from one account to another. Get that current token counts of an account, approve whether it's third party account can transfer tokens and get the honor of the specific tokens. So these are the functionalities given to us by the year 21. So now, simply, if I go inside this year, see 17 given URI storage. You can check out those code in the node modules. Then added it up in Zeplin. Here you will find token and C7 don't even token like this. So here you can find everything, all the functions and all. So simply, when we are creating and deploying our project, we have to send his name and symbol. So this name, this name is used to tell outset contracts and applications that use of this token. And that symbol also helps in providing compatibility with the ERC tokens standard. It provides outset programs with the tokens shorthand name. So these are coming from here. That is, this constructor initializes the contract by setting a name and operator token connection. Then we have this owner state variable. That core of an ear C7 to T1 token is the owners private variable, which is a map of that token ID and its owner address. You can see here, the owner's state variable contains that token ID and its owners address. For example, here, the Alice has the NFT id one and above has NF DID to. The owner state variable will contain these following and j's, that is token ID and to which the address belongs to. So this is the owner's radio, but India is a function called Owner off. Let's see if it's not there, but we hate this one. We have this function called owner of which looks up this variable, that is this owners variable, and returns the corresponding entry if it finds one with respect to the token ID which is sent to this function. The next thing, which is an important state variable is that balances similar to ERC. 20 years is 721 has their balances private variable that keeps track of the whole length of each account. So for example, when Alice and Bob has an NFT, each variable would contain the entries like this that is addressed and that token count. How many tokens or NFT does this address half, we can call it through this balances state variable which is here. So these are all inside this smart contract. We will be using only the ones which are required. If you want. You can explore as much as you want. Then in these balances, we have this balance of methane, which looks up to this variable, that is balances variable and returns a corresponding entry. These are, this is another function which you can use. Then we have this main thing, luncheon, which will help us to create a new token. That means internal function helps us to updates the owners count in their balances variable adds the owners of that token ID in the owner's variable. So this is what Mint does. That is, if Alice means a new NFT token ID tree, the owners and balances variable are updated like this, as shown in this diagram. Then then after we have another way to maintain that is called a safe mint, which additionally verifies that the new owner can receive ER's is having 212 or not. So this is another way to use the main thing, which is also preferable in most of the cases. This safe means you can find C, safe mint. So these are all functions which are returned inside this contract. This is the main function which we will use it in our code as Vince here in that demo. So you can see this mint function being used. So this main function takes an address to which the NFT should be maintained and that token ID. Then it checks that the address should not be null or empty, something like that. And whether this token ID exists or not. And then it simply changes that balances variable and the owners variable. Then it emit an event that is transfer event on its own. So these are all going behind the code that we don't know, but these are all working. That is this transfer function. For this transfer function also we have this workflow that is yet to workflows. Now, let's talk about that. Transfer functions. Like ERC 20 years is 721 has two workflows to transfer tokens from one address to another. Deaf first one is the simple transfer function, where the owner transfers token. And the second one is the transfer from function, where a third party will have that due to transfer that token. In the code. If you go to this year's is 721, which is present in the node modules. You can see here. We have this transfer function here. So it accepts from two and token. And then there are some required check that the owner of the token is what we're sending from. And two should not be 0 at rest. That is, it should be some valid address. And then that core part of this function is to update the balances and the owners variable, which you can see here. So for example, when Alice here has NFT of ID1 and ID3, and Bob has NFT id2. Then the balances are as follows. That is, Alice has to token count and Bob has one. But when Alice transfers that token ID3 to Charlie, then that new balance will be like this. That is, the address value for Token ID trees are they date from Alice to Charlie in the owner's variable. They are counts are also updated in that balances variable accordingly. You can see those in the diagram. This is how it is done. Then we have that transfer from function. It is the earlier one was not exposed to the user because it was internal. But that transfer function is used to transfer tokens when third parties are involved. And it transfers the tokens on behalf of the owner. So here you can see it has some conditions to check and it makes sure that all the conditions are true. That is, message that's sent, that it is who is calling this function is the owner. The message the sender has been approved electrons to transfer that to On behalf of the owner. Owner has approved to transfer all the tokens. If any one of any of them is true. It calls that transfer function internally. And definitely inside it. It has a proven other functions as well. So here are their functions. We have talked about transfer. We have talked about main thing and all safe means. Like this. We have talked a lot of functions. And if you see the NFC code, get is this counter variable. So you might be thinking, what is this counter variable? So this counter is coming from, appends a plane, contracts, utils, counters. So let's go to open Zeplin contracts, then utils and counters. See, now we have this counter and inside it, counters and then inside it we have this counter struct and some functions. So here when we write counters dot counter, you can understand why, because this is the counters library and discounted they discounters dot counter. Then we get the value. That is why we write here like this because earlier I was confused. What is this transfer that is counters, dot counter and all. But when you go inside their code, then you will understand, okay, this is the real meaning of it. Now, you might be thinking, okay, when we go inside this truck, then how we are able to call the increment function, which is outside the struct. See here we have this increment function, decrement function, reset. These functions we have we were able to call it because of this line that is using counters. Counters that counter. That's it. Because of this line, we were directly able to access these functions from this variable. If I removed it, if I remove this, you can see it will start showing error. Just remember this is just a simple function which starts from 0. And when we increment it, just increment one value at a time. That's it. We might be thinking to get a value. Why didn't we do it like this? Var I is equal to 0 and then I plus, plus like this. The main reason we haven't done the increment like this because in this case, we can change the I value later on, something like 20 or 30. But we don't want this. We only want the value to be incremented by one. And in this counters library, the only option is just to increment by one or decrement by one. There is nothing such to set the value of the counter. So that is the main use of this counter. Now, at the very top, you can see we wear, we are importing these two files. You have understood that counters file. And this is just that contract which contains the implementation of the ERC 721 standards. There is another function, or you can say access modifier of open Zeplin, which is known as ownable. I will just show you open Zeplin contracts access than ownable dots. So this will be used by you a lot in the later projects because this helps us to set up access control on our smart contract. So that only the owner of the smart contract can mean the NFP is. So if you'd like to if you'd like to make sure that anyone can mean than if they didn't, you shouldn't use this library or else you should use it by just writing here. Game item is ERC 721 and then comma o navel, like this. So now only the owner can call this contract. That's it. For this function to be only access to owner we can, we should write only owner. Like this. This is the modifier which we have to use and it will make sure this function will be called only by the owner. So I hope you have understood these concepts. In the next video. When we will be creating our own NFT, you will understand all these implementations. And now I just wanted to tell you how the how internally this contract is working. Now, I will just give me the summary. In the open Zeplin there getters our name. When we are calling the constructor, we are sending this name and symbol. So the name field is used to specify that name, which other contracts and applications can use to identify it. The symbol is used to define us shorthand name or symbol for that token. Total supply function is used to specify that total supply of tokens on the blockchain that's applied does not have to be persistent. Then balance of returns, the number of NFT is that address owns. So definitely value-add creating an NFT marketplace, you should know how many days this particular my Thomas address or whatever address owns. Then we have the ownership responsibilities. First one is owner of this function returns the owner of free tokens and dress because yours is having 21 tokens, non-fungible and unique data represented on the blockchain by ID. This ID can be used by other users, contracts and applications to determine who owns that token. You know, every image, we give it the id. Then we have the approved function. This function allows or approves and other entity alterity to transfer tokens on behalf of the owner. This is also very important function which you should know, which is an internal part of the C7 to T1 contract, then we have take ownership. It is an optional function, that function similarly to a withdrawal function, in that it can be called by an external party to veto tokens from another user's account. As such, take ownership can be used when the user has been approved to own a specified amount of tokens. And vicious to redraw those tokens from that balance of another user. Then we have other responsibilities as well that is transferred. It is another transfer function. It enables that to honor, to transfer it to another user. Similarly, how digital tokens or points work? Then we have to turn off owner by index. It is recommended but are optional function. Each owner may only own multiple NFT is concurrently. However, each NFP is identified by a unique ID. And it can become difficult to keep track of ideas over time, as it is, the contracts towards these ideas in it. And the token off owner by index function allows us to retrieve that. This was about the ownership functions. Then we have the function of metadata. Metadata. This optional features provides an interface to discover the metadata are linking to the data associated with ID token. Then we have events. This is very much important that these two events, that is transfer event and they approve event. That transfer event is triggered when the ownership changes from one individual to another. It emits information about the account that transfer that token, the account that received the token and the transfer token. That is the idea. So whenever we call any function or minting function, anything like that, then this transfer event is called. The log has been saved in that blockchain. Then we have this blue function. This event is fired whenever a user grants and other user ownership of the token whenever the proof on Chinese executing. So this is an event which is being emitted by the approved function. It emits information about which account currently owns the token, which account has been granted permission to acquire ownership of that token, the future. And which token, that is the idea has been granted permission to transfer ownership. So I hope you have understood a lot about how the ERC 721 opens up being contract works. Thank you. 7. ERC 721 contract using Openzeppelin: Hi, welcome back. In this session, we will create our solid the contract using the append step plane library. Or you can say package suggests you can Google as well, open sapling. Then click on the first link that is presently contracts, and you can read what it is. So now to create our ERC 721 smart contract, we will use this library. Open Zeplin is a library of modular, reversible, secure, smart contracts from the ATM network, written in solidity. It allows us to leverage than that tested and community reviewed contracts for its purpose and can significantly reduce the development time of applications. So in simple words, it gives us predefined code which we will use in our app. That's nothing much. To install it. You just simply have to do it like any other NPM package, NPM install. And then append Lynn slash contracts. That's a presenter. Now it's working. You can just go to Docs and see that Dawkins, ERC 27211151, like this. If you right-click on 721, you can see this code and on. I will also use the same cord. That's it. Nothing fancy. I will just use the same code and change the name. That is that class contract name these days. Simply. If you want, you can read the whole documentation as well for your own understanding. Okay. I think I did some mistake. C. C. I will just copy from here on the base. Okay. That's spelling. Okay. I did the spelling mistake. It's fine. Now, that Contracts folder simply create a new file called my NFT dots sold. So first we will always use this line of code. Like this. That is a debate that we have to specify the license and parcel of solid DVI using. Then I have to import the pen Zeplin lab really lean on tracks to eLC 721, C7 going d1 dot zone. So you might be thinking how I got this. So if you click on 721, see here, it's not there, but we will use these as well. So you can just copy it, paste it down here. That is E SS7 to D1 URI storage and counters dots sold. So these inputs from a principle and it is 721721 URI, storage and counters have their own purpose. Years it will do 721 that contains the implementation of the ERC 17 different standard which are NFT smart contract will inherit. Counters is just helping us increment that token IDs and can only be incremented or decremented by one. Er, C7, C8, and T1 URI storage helps in the tracking URI, which is stored in. Storage pointing to NFT metadata. So these are the use cases that is the meaning of these inputs. Now, let's create our contract. I will name it my NFT. Then it is extending to see 721 URI's to which this is one. This is a kind of inheritance. You can say nothing much. So just using counters. Don't start countered. And founders can. So we are using these counters to help us increment that identify as for the tokens we meet, we're also use create, creating this token ID variable to keep track of all the tokens we have issued. Now, let's create the constructor. Constructor will take a string mammary name, string memory, symbol C 721. And we will send this name and symbol. The error is gone because we have to write these lines. If you go to the open Zeplin, see this other code I have been using, that's it. You can read. If you want to understand more. Obviously, everything has its own purpose. Now, after this constructor, I will create a function. And F, D, which will address the recipient string memory. Uri. It will be a lake, and it will return this value that is an integer. Now what? I will write this, this line of code c. This, I will write token IDs, that increment. First thing, then you went to 56, new item ID. We'll do two IDs, that current id. Then I'm calling this main function which is being inherited in this contract. Some main recipient and new item ID. Then said, can you add a new item ID? And token URI will be this. And simply at the very end, return new MID. So now what this function mean? We have our function main NFT that allows us to meet and NFV. We pass an argument called recipient with specified that address that will receive the NFT string memory token URI is a string that should result to adjacent document that describes the NFT my data, which we will do it in the upcoming videos. And NFP is metadata is really what brings it to life, allowing it to have conflict gable properties such as name, description, image, and other attributes. Later on we will create a metadata file. In the end of the function, a tense, a number that represent the ID of the freshly minted NFT, this one. So this is the code or the solidity contract for minting and NFT. You can get the same contract here in the documentation as well. If you want, you can read it or try this, but the code, or you can just understand here as this is a game item and an hour, an hour is there. Nfp, that's it. This is creating an FTE for the same item. So that's it for this video. I hope you have written that code here. So in the next video, we will work on the IPFS and our images. Thank you and see you in the next session. 8. Uploading images to Pinata: Hi, Welcome back. Now to proceed further. First we need some images. You can use whatever image you want to be an NFT. I will simply Google. Download free NFT art and click on this Pixabay website, which gives us free images like this. So I will use this image. This is, this looks good as well. I'm just checking out the images. Images are fine. This evidence simply click on Free Download. K averages this smaller resolution, and click on Download. This. I have this downloaded. Download, whatever image you want. And inside the root directory, create a folder called data. And inside it create a folder called images. Okay? You have this, my images. And I will just paste those images in this folder. This image, smiling ape, you can just see, just write my name. And this second image is this. I would just download it as well and paste it in the Images folder. And it's good, does seem Sun, the Sun. So I have these images in the project folder. Now. For uploading it to the blockchain, I will use pinata, that is an IPFS. It simply uploading images to the blockchain is very expensive since they are large in size. The best practice is to only upload the link of your image to the blockchain and store your image on an IPFS. Pinata allows you to upload NFT images for free using IPFS protocol. This is a distributed file sharing system. Simply Google beneath data. See, create a new account here. And then simply login with your credentials. Then you will be redirected to the dashboard. And here you have to upload your images like this. Just simply click on this Upload button file. I will select the file Web three images first, that's my link. And then click on Upload button. File uploaded successfully, C. And then another file, which is the Simpson. Like this. This is also uploaded. So now what we are doing is the steps required for us to create the NFT. That is, first, we have to upload the image to die PFS and then also the metadata of the IPS. In the next video, we will be creating our My dad did that file as well. Thank you. 9. Create Meta data and upload to Pinata: In this session, we will create the NFC mightily done. Our task is to create a JSON file for each image and populate it with data including the pinata image URL, that is this one. See this image. If I click on this, we will be we can see that image file, which is stored in the IPFS. And we need this URL to be pasted in the NFT made up the data file. Okay? And this is a format which is calm, client and understandable by platforms like NFT marketplace. That is this NFT meta-data, fine. Now, for that, simply, inside them make their data folder that is outside the images, create a new file called the same name as the image file of this smiling a dot json. So this is the METAR data smiling images file. You simply have to write this line of code, this adjacent file. So Dan name is my name a description. My first NFT is a smiling. Then this image is the URL, that is this URL. We have to paste this URL here. Then the F4 key will be at three builds, which is an array. And trade type. Background value. What is the background of this image? Something like blue. I will just write dark blue. That's it. As far the next image, again, just can simply click on this. We're not in the images in that metadata to it. I'm just selecting it here. You can write it wherever you want. Json file. Copy this code of the smiling either Jason, paste it. Now, genes that values the Simpson. My sick get enough gain. It is a cool Simpson. Now, if I click on this, the background is something like orange, light orange. And the image I have copied this, that is the URL of the image, the IPFS. To save it to simply if you go to the meter data, see we have this JSON file and the images, we have the image. Okay? Now we have to upload files to pinata as well. We will also add our this JSON metadata files to IPFS so that we can pass it to that token contract. Storing metadata file directly on the blockchain is still very expensive. Hence, we add an additional layer of abstraction and upload these days sent to the Cloud as well. And simply stored a URL pointing to this file. You simply file smiling, I upload. And then we have the smiley ape. And then that's Simpson. Find this one. Okay? So now we have done all that necessary, required steps that is uploading our image. Do I put IPFS, then uploading the NFT metadata files to IPFS. And remember, we will use this JSON file URL later on. It is this one. If I click on that simpson, Let's see what happens that adjacent values. See. We have the image link here. This working. So that's all for this video in the next session are there in the next module, we will deploy this smart contract to the test network and see what happens. Thank you. See you in the next session. 10. Writing the deployment script: Now that our contract is written and our hard hat is also been configured, as well as it's ready to be deployed. V, it's time to write our contract deploying deployment script. Navigate to the scripts folder, create a new file called deploy dot js. Now, at first, where we will require that eater dependency acquired. It is ethers from the hardhead dependency. Then we will write and sing function called main. Then we will create an instance of our contract. It is, we'll get the contracts, ethers that get contract tree, my NFT, and this is the contract named see here, my NFT. Then we will simply writes in the small letter my end if D is equal to await. Got big Dell, my NFT. Deploy. When we are deploying the contract, see it in the constructor. It is asking a name and symbol for our NFT. Name is my first. And and the and symbol will be mine. And see like this. Then simply right away, my NFT deployed. And we will console.log that contract address that is deployed address where it's being deployed in the stadium network. The diploid two, and then my NFT address. We have uses a scene because we are using a weight a lot of time. Then I will just call the function. And then the good thing, if everything is okay, then I will just exit with 0. Or else, if we catch any error, then I will console love that. I love this exit issue. That contract factory. See, I have written that code, but let's try to understand that lines. It is line-by-line. Let's try to understand that contract factory. It test.js is an abstract used to deploy new contracts. So this NFT here is a factory for instances of our NFT contract. When using the harder it tells plugin contract, factory and contract instances. I've connected to the first signer by default. Calling deploy on a contract will start the deployment and return a promise that results to a contract. This is the object that has a method for each hour of our contract function that is, after being. We can also call whatever function we want in debt contract, that smart contract. So the deployment script is written. It's time to deploy our contract. Let's check if it will work or not. That's I would like to create a new terminal. The deployment command is and bx or had run scripts. And then the scripts we have deployed dot js network link to be. Let's see. Obviously it will take some time. First, it's being compiled. Code. You can see one new folder called artifacts. It's being created. Now let's wait and see what happens, whether we will get an edit or it's successfully deployed. All these hard hat code or this NP x around deployed. This can be read or seen in their documentation as well. These are nothing fancy. Stuff is very simple. But now we just have to wait. Sometimes I know there are a lot of errors in it. Sometimes we're not able to deploy for some silly mistakes. Let's see. I hope I haven't done any. So you can see our contract is successfully deployed to this address. Make sure you copy this address here. I will just read the comment and paste it here so that I don't lose it. But luckily, it has taken some time, but it's fine. Now to check whether it's to check that deployed contract, we can use that inky be eaters can see that transaction which happened right now. Let's see. Here I have read for th second ago from this public key that is the from address is our Meta mass address. Again, I wanted to just see Degas E, D, E D, C. This is That's it. We have successfully deployed our first contract. This contract address will be used later on. And so that's why I have just copied it. You also do the same. That's all for this session. In the next module, we will make our NFT. Thank you. 11. Creating a minting script: Hi, welcome back. Earlier, we have successfully deployed our smart contract to the Itanium destiny and caught our contract address. In this session, we will meet our LFTs. So what is meaning? Meaning the first to the process of turning a digital file into an NFT on the titanium blockchain. This NFT is stored on the de-centralized database, making it impossible to edit, modify, or delete. Now, for that to happen, we have to install a library called a verb tree. We will need the alchemy library to interact with that contract deployed. Therefore, you should install this at first. Alchemy web tree is similar to eaters, but an enhanced web tree library used to make requests to the Akkadian blockchain easier. So in that terminal, we have to use this command. Now open up your project. Here. Simply npm. Install ALL CH slash alchemy hyphen three. It will take some time to be installed. And after that, our next task is to create our minting script. So earlier we have is deployed script, same like that. Create a new file, insights script and name. It meant NFT dot j is the main thing process need some variables like your MetaMask keys and that alchemy URL. So far the melanomas keys simply require that dot ENV back cage. Then that alchemy Web three, which we just installed at these create Kimmy three equal to. Require. This tree. Then create an instance that is our URL is processed. The ENV. Gamey. You like this. Now, we have to grab our contract ABI and create an instance of our contract. Aba is that interface to interact with the smart contract which we have deployed. Hard hat has generated an ABF or our smart contract, which is stored in artifacts folder. See here, contracts, my NFT and then we have mine FT dot json files. This is the ABA am talking about. It is important that we have that smart contract address which we have deployed. And this is this smart contract address. We will use the Web three contract method to create our contract instance using the ABA and this address. Let's do it. Yet I will let const contract is equal to, is equal to constant require will go up a folder, then artifacts than corn tracks. Then my NFP dots soul than mine. If d dot js, this, then that contract address, I will write it here on track. Address is equal to this. And then I will create the contract instance, tree, contract instance. So I will just name it. And if the contract is equal to new Web three, dot dot contract, and it will accept the contract ABI on track dot aba and contract address. So that's it. That's how it is done. Now, we will define the minting function. Let's create the front chin here and name it meant an F D. It will be a sinc function which will accept a token URI. This token URL. I will tell you later on, what is it, what it is. But right now, just focus on this piece of code. Let's write it down at first. Nonce is equal to await. Web three dots it. The Get Transaction Count processes that ENV, not wallet, public key, latest. Then we will sign a transaction. And first we will create a transaction object. It will accept from process the ENV not let private key, the public key only. Well, let public key then to contract address. Then nonce. Nonce. Then gas 500, housing, then max d fee. But gas will give it the value 199999987. And data it is NFT contract methods. That meant NFT. We will write versus the ENV dot. Let public key. Can you add a code ABA? So that's it. Now, let's break that code down. Nonce is used to keep track of the number of transactions that have been sent from your address. This is necessary for security purposes to prevent replay attacks. The from is the original or the initiator of that transaction. This is our public address. That two key defers to the contract address we use to interact with gas is the estimated gas needed to complete the transaction. Max. Priority fee per gas means it is estimated fee to bid. But gas and data is that computation you want to perform? Richard is maintaining an NFT. This is the code. Now we have this transaction with us. Then the next we have to sign this transaction. The sign this transaction in order to send it off. Here we will use our private key for days. We make use of the Web three dots it functions. This will give you the transaction hash in order to verify that our transaction was effectively mind and not dropped off by the network. Now, let's say Code sign transaction is equal to await Web three accounts, that sign transaction. This transaction object and the process that ENV the vallate private key, this thing, private key. Then section receptor is called Web 38 dots and signed transaction. We have same transition dot raw transaction. Then simply we will write console.log, transaction receipt. Learn JSON dot stringify, transaction G, C. Okay, Save. Now we have completed our main thing script. Now it's time we call this meant NFT function. And the end of this file, that meant NFT functions requires a token URI parameter here that refers to that JSON document where the metadata is stored in Kenyatta. So what I mean by that is that might tell me that file which we have uploaded in the opinion data. This this unit. Okay. Simply we will call main NFT function. Here. That I'm mentally tough file, not the image file. Just remember that JSON file. And one one-by-one. Yep, Let's save it. Now it's time to open our domain. We'll just, I've been here in new terminal like this. And write the command node scrapes meant and f, d dot js. And press Enter. Let's see if some areas there are everything is working fine. Sometimes I have what I have encountered is I haven't got the print statement and terminal just got stuck here. No. This is not the case in our we have this proper transaction receipt. You can see I guess it has properly main dead. So that's it. If you want. Let's go and check in our contract address here as well. Earlier it was this transaction. If I refresh, and you can see our mint NFP is also done. So you can just celebrate, we have successfully wrote the script and maintain our first NFT. In the next video, we will view this NFT in our wallet. Or if you want. I can also mean the other NFT as well. Let's see. I will just copy does Simpson, simpson here as well. And then in our code here, I will change it to that data file URL. And again, I will just go here and type the same code. Node, scrapes main, NFT dot js, and press Enter. Let's see. Let's see if it is showing any error or do we know it is also done? It is very fast right now. I'm, I'm very glad. That same thing. Let's check. In our contract address. Do we have a new yes. We have districting second ago. We have this new transaction here, which is the main NFT. So that's it. In the next video, we will view our NFT in that MetaMask wallet. Thank you for watching. See you in the next session. 12. View NFT in Metamask wallet: Hey, welcome back. In the last session, we have successfully maintain our NFA. In this video, we will view our NFT in our MetaMask wallet. Now for that, we need some information and we have to visit this ring ether scan, our contract address. I have already done that. In this transaction hash. Suppose this one, the first NFT we maintain. This contract address is required, that is this contract address and this token ID is required because we have to paste these details in the MetaMask wallet in order, in order for our NFT to be viewed. And that's it. So let's see. I'm going to move my mask. And if D The first, we have to make sure we are in that incubator desk network. Then we have to go to this NFT section and click on Import NFT. See here this is the contract at this which is required. Just paste that contract address and the id which is one. And I will just click on Import. Let's see. You can see that my first NFT is now written here. Definitely. It will, the image will take some time, I believe. But at least it is being fetched from your account or from the blockchain. Will just try to refresh it and do something that's C. Also. If you want, you can go and upload your other NFT as well. Just refresh it multiple times. Let's see. It's working. It's working. See, smiling. Name is also correct. Only the image. It's taking too much time, I believe. You can see here our NFT or that smiling is successfully showing in our MetaMask wallet. So that's it. This part is done. If you want. You can import the other NFT as well. I will just show it here and then try to sell it in the marketplace in the next video. That's all for today. Thank you. 13. View and Sell your NFT in OpenSea: Hi, welcome back. So we have successfully viewed our NFT in the Meta mask. Now it's time. We list our NFT in the open sea market place. So if you write a, C, C is that piRNA marketplace for nf this it also has the most NFT activity by far, with all that time trading volume in billions, making it ideal place to get started with trading. And if these to login into appends, see we should have a valid and since we are using rinky bit test network, so that is why we have to use the net of a pensive. We cannot use this main neat stuff because our NFT is also sent on that testlet. So if we connect our volunteer, it won't show. For that to show, we have to go and write a fancy designated, this designates that are pensive.io. See here. Then we have to connect our MetaMask wallet. Just click on this. Notification, will pop up. Just simply login to your MetaMask wallet. And see. We have our two. Nft is. Just remember, I haven't view imported this NFT in them at damask wallet, but that doesn't mean open sea or it is not in our contract address, since you can see both days where sent to the test net with this MetaMask wallet. And you might be thinking how this is here. This I already bought from this marketplace, and I will also show you how to buy your own LFTs in that test market as well. Simply. Now, it's time. We sell this NFT in this test market. So simply when I click on it, you can see this background dark blue. I write it in the METAR data file. And this is the description. Now I will simply click on this cell button. Here. I will write a fixed amount of suppose 0.01 e duration, one month, and click on complete listing. So simply to enter the price duration. And that's it. It will show a progress indicator and append a pure voted to approve that transaction. C. Here, I will simply click on Approve. That is confirm. Now, simply sign saying that transaction. And that's it. We have successfully listed our NFC to sell in that test market. And the same thing can be done in the main net as well. If you have the editors, definitely you can do it. See our NFP is now in sale. So cool. This so good. If you want, you can explore other LFTs as well. As I told you I bought that. Suppose. You want to buy or you like some NFT. Now? Yeah, cryptocurrency, they can be bought. I will just quickly click on binary 0 eater, I guess it's for free. I will just simply click on Checkout. Okay. Sorry. It will go to the wallet. This right now I don't want, I want to buy directly from here any NFT, 0.01, at least. I don't want this free stuff. Again, this is here. And if I write by now and sort by recently listed Dan, see, our NFT is now here. Same as this. There are a lot of other NFT is camping with potato. I like this NFT. I will just click on this night, 0.05. I will click on Buy Now. And simply, I will check it out. This is in the, this is all happening in that test network. See, my test eaters will be used here. Let's see what happens. Status is yes. Now I have what? This NFT. And if you want to see, if you go to the profile section and see this NFT is now here, and if you want, I guess you can sell it now. I don't know. Yeah. Since you have this, you can now sell as well. So yeah, that's it. I hope you have enjoyed this course. Also, I will upload or attach the whole code of the solidity or this application. Feel free to check if you have any doubt or if you did anything wrong in your own code, are simply upload that code in your GitHub so that you can show it in your resume. Thank you very much, and keep practicing.