[Guide] How to create a digital item (ERC-721 token) and sell it OpenSea.io exchange

This is a guide for understanding how to create Non Fungible Tokens (NFTs) to represent digital items and how to sell these tokens for Ether.  This guide is a bit of a beast but we wanted to make the minting process super simple and have you making your very own smart contracts in no time.

But before we do - If you are not familiar with the terms Non Fungible Token (NFT) or Smart contract, or want more clarity on what they are, have a read of this. If you are new to Blockchain this is pretty important.

If your into solidity coding or you already know what you are doing, just go straight to https://mintable.app/create and get going.

What are ERC-721 or NFTs?

If you are a true crypto head- you have probably heard about the smart contract standard ERC-721  and its term as a Non Fungible Token (NFT). Most often NFTs (digital items) are discussed as game changing technology and will revolutionize the world we live in  - allowing peer to peer trading and establishing trust in ownership among digital items.

These NFTs have been around since 2017 gaining notoriety for their use in crypto collectable games like Crypto kitties, Axies, Gods Unchained and a whole raft of others. They work very well for collectable games and give us a glimpse of their potential. But there are other use cases that most people don’t even begin to consider...

Outside of digital cats and card games how can they be used? What else can be tokenized as a digital item? How do you make your digital item? How can you actually use them to exchange your own digital items?

Mintable has the answer and this guide is here to help you do just that. Read on and we will show you how to create your own NFT for anything you like and how you can sell that NFT for Ether - all using the blockchain without needing any documentation or knowledge.

 

Sections in this guide:

  1. What can you create using Mintable?
  2. How do you represent an NFT as an asset?
  3. How to make your own smart contract and mint tokens using Mintable’s creator
  4. How to sell your tokens on OpenSea

How to create ERC-721 tokens using Mintable?

Mintable allows you to create your very own ERC-721 standard smart contract and mint non fungible tokens for that contract. - crypto-nerd talk

Mintable lets you create a digital item that you can sell for cryptocurrencies on NFT marketplaces. So you can take a picture, some characteristics, give it a name, make it rare, and sell away for a profit. With each smart contract you can create multiple tokens and these tokens can be used to represent your digital items.

Sell unique content via mintable!

Here is an example: You are a graphic designer and you can make really cute or scary monsters. You make 50 of these unique cute things, and create a smart contract using Mintable called “My Scary Monsters - Limited Edition 2019”.

Then each token, is actually a picture of each one of your monsters. You can sell each token for whatever price you’d like, and if someone wants it - they can buy it!

If you promise to only make X amount - or have a social media following - users will find value in your creations. These types of tokens are best for people who have social media followings like Youtube creators, Twitch Streamers, or Twitter personalities.

Ok what else can I do with my NFTs or ERC-721s?

Mintable also lets you manage all of your current digital items you have - such as any Gods Unchained Cards, Axies, Blockchain Cuties, CryptoRome Items, Crypto Assault units…. And the list goes on. It’s the easiest way to transfer, browse, and interact with your digital items - guaranteed. 3 clicks to transfer an item and it doesn’t matter if your wallet even knows about your token (some wallets don’t display your items, but as long as you own it, it will work)!

How is Mintable Unique

Dapps like cryptokitties and Marble cards have their own smart contracts and tokens however what the tokens represent is already predetermined. In these DApps the tokens you own are restricted in what they represent; Cryptokitties tokens represent a line of code and Marble Cards represent a web link.

Mintable is unique because it allows you to create and own the smart contract. You decide what the contract is for and you choose what the tokens represent and how many there are.

How can you represent your asset as an NFT ERC-721 in the real world?

There are a number of ways you can use your tokens, some of these include:

  • Establishing ownership of an item external to the token
  • Establishing who is allowed access to content or locations
  • Linking the token owner to a web URL, a photo, video or other web based asset
  • Establishing ownership of something in the tokens Metadata
  • Creating tokenized assets that you are a middle man for
  • Creating content to sell
  • Tokenizing content
  • Tokenizing anything that could have value
  • Creating value with a token and data - if you have an online store you can accept that token as a discount card
  • Utilizing tokens for your business in the form of credit, discounts, or coupons
  • Event ticketing as a token
  • The list goes on….

There are many more ways to use them but this is where you need to get creative

Example 2: You might be a photographer who wants to create a smart contract to sell your photography on the blockchain. You can create the smart contract on Mintable and then mint tokens to represent the photos you are selling. Each token could relate to a different photo and give the owner of that token ownership of a specific photo that token relates to. You can then sell these tokens with the smart contract ensuring the transaction works and is successful.

Don’t worry if you aren’t a photographer, there are many other things you can create and sell with Mintable:

Other Ideas:

  • Create your own crypto collectable cards (like crypto kitties or Marble cards)
  • Sell tickets to an event where whoever owns the token gets access
  • Sell your digital photography or digital artwork
  • Design new content such as characters or badges
  • Raise funds for a project by selling tokens which give rights to something (just like Kickstarter does)
  • Sell access to videos or audio content you have created
  • Create a link between your real world business and the token (could be a discount card, a form of credit)
  • Create public verification of some data: such as: “I published here publically this patent idea on the day of XYZ” for public proof (its always on the blockchain!)
  • Sell rights to the tokenized asset if you can mediate the content transfer

Again you have complete freedom to get creative here, using Mintable there is really no limit to what you can create. This is a new market full of new opportunities. Start experimenting and see what works.

At the bottom will be a list of 25 example items you can profit from using Mintable

Ok, so now we have some ideas on what to create lets look at the how you can create your smart contracts with Mintable’s ‘Create’ function

Mintable offers an easy to use Smart Contract generator that takes you through the process of creating ERC-721 standard contracts and NFTs step by step.

Don’t worry if you don’t know how to code, we’ve got your back. With Mintable you can create a smart contract without any knowledge of how to code. We do all of that for you, all you have to do is put in the right information when prompted.

 


Required to create a smart contract on Mintable:

  1. A Browser with a wallet
      • Chrome or Firefox with Metamask extension
      • Brave (includes Metamask)
  1. A Mobile Wallet
    • Either Trust wallet, Status, Coinbase wallet

If you don’t know about Metamask it is a free extension for your Chrome or Firefox browser which lets you interact with decentralised blockchain apps (like Mintable) right from your standard internet browser. Don’t worry its super safe, its what we use personally to connect to DApps. Visit Metamask and follow the steps to install it.

How to make an ERC-721 (NFT) smart contract

  1. Use the Mintable Creator to generator a ERC-721 NFT smart contract.
  2. When using Mintable - the smart contract you are creating will hold your ERC-721 tokens inside it. This is the ‘store’ for your items. If you wanted to make a Pokemon Card Game clone - the name of the smart contract would be Pokemon cards. Where each token in the contract would have its own name, like pikachu, charizard, etc
  3. The first token made in the contract is made when you create the contract. You can think of this as your “genesis” token. It can contain extra data about the contract, or it can just be another normal token. It will have an id of 0 (zero)

Connect your Ethereum wallet to Mintable.app

When you go to Mintable you will be automatically prompted to connect Metamask. Once you’re connected you can begin creating your smart contract. 

This is the page displayed when your wallet is not connected or you are connecting to the blockchain. If this page does not disappear after a few seconds - refresh the page.

Connect your metamask wallet to Mintable.app

Connect your metamask wallet to Mintable.app

How to create your Smart Contract

Go to the ‘create’ page at https://mintable.app/create. You can either click on quick create if you know what you are doing or click on guide me to have us take you through the process step by step. We will take you through each of the Smart Contract fields mentioned above and all you need to do is put in the information you want.

Easily Create an ERC-721 smat contract on the ethereum blockchain using Mintable

Easily Create an ERC-721 smart contract on the ethereum blockchain using Mintable

If you know what you are making this will take you less than 1 minute!

Now were going to run through the fields you need to fill out to customize your Smart Contract.

Mintable’s Smart Contract creator currently lets you customize your contract and ERC-721s using the following fields:

  • Contract Name

This is the name of the smart contract you are creating. In the case of Crypto Kitties the contract name might be “Crypto Kitties”. Each token you create under this smart contract will carry this contract name. In the example of a “Magic the Gatherings Vitalik Series “ as the name of the contract and the symbol as MTG  it would be displayed as:

This will appear on all tokens you mint for your smart contract.

  • Contract Symbol

This is a short code that identifies the smart contract your token is part of.

You can choose what your contract code is. In the case of Cryptokitties their code might be called  CRK (for Cryptokitties). All Cryptokitties tokens would have this symbol indicating that they are part of the Cryptokitties smart contract.

This will also appear on all tokens you mint for your smart contract.

  • Batch Minting

Batch minting is a new feature to Mintable Beta which allows you to create multiple tokens for your smart contract in just one click, saving you a ton of time (rather than creating each token individually).

The more tokens you want to mint per batch the higher the minting fee, however a minting fee is payable only once for each Smart contract. After that you can continue to mint tokens on that same contract for no additional minting fee.

Batch Minting allows for your token to be cloned up to 40 times in one transaction. If you don't use batch minting, the only way to make 10 tokens, is to mint 1 token 10 times - effectively sending 10 transactions and paying the transaction fees 10 times.

Batch Minting can be unlocked for a one time fee - if you pay $10 your smart contract will ALWAYS be able to batch mint any amount of tokens up to 10 - in one transaction. Saving you on gas/transaction costs.

So if you pay for batch minting of 40 tokens you can come back and mint 40 more at another time without paying another fee ever - its one time then done. (You will still have to pay the Ethereum gas transaction fee for processing the transaction).

I know, pretty awesome right 🙂

  • A web URL

You can use the web URL to link your token to a web based asset like an online document, article or web page. The asset it is relating to must be stored online. Alternatively this can be used to add a picture to your NFT which shows up when you or someone else views the NFT an app like Mintable. If you want to display an image - make sure your url ends in a file format for a picture such as: (.png, .jpg, .gif, etc)

If you are adding an image this needs to be uploaded on the internet in a place like google docs or imgur. Once uploaded just copy the link for the image (Making sure it ends in an extension file like .jpg or .png) and put that in the URL box on Mintable

  • 3 rows of free Metadata - (if you don't use our API or Batch Minting)

In the example of Cryptokittie tokens the Metadata describes the individual characteristics of the cat that together make it unique as a collectable, like its eye colour and fur colour.

If you don't use our API you will only have 3 fields of metadata that is stored directly on the blockchain and it will not be compatible with other services only Mintable.app.

  • Use our API 

If you want to sell your token on OpenSea - you need to use our API to make it compatible with OpenSea

Metadata is data that defines your token and makes it unique. You can add anything as meta data - here is an example of a token for a coupon code for a business. Metadata is in orange. 

Using the Mintable API to host your data means you can include any data you want and we will generate you a URL that is stored on the smart contract. The URL will look like this:

Token Name: Bobs Bike Store 
Symbol: BBS 
URL: Use our API 
Metadata: 
Title: Free tires with a purchase of a frame 
Name: Free tires with a purchase of a frame 
Description: This card can be redeemed at bobs bike store for free tires
 whenever you purchase a complete frame as well. 
Transfer the token to the address listed on bobsbikestore.com 
to redeem with your order 
URL: Link to redeem 
Image: Image of coupon 
…. You can add up to 20 extra fields so whatever information you want can go here
  • Title, Categories and Descriptions

We have added categories, titles, descriptions, that will not be on the blockchain but instead used for displaying your contracts on Mintable.app and OpenSea. So if you wanted to sell your tokens, you would have a title and description already written for others to view. 

  • Fees

Creating a new smart contract will incur a small fee in Ether. This is made up of a Mintable minting fee which is fixed depending on the type of smart contract you want to create and the gas fee which is needed to process the transaction. The gas fee listed in metamask seems high - because the transaction is DEPLOYING a new smart contract to the blockchain. This is expensive. The gas limit is 3,500,000 gwei and should not be changed or your transaction will fail. This is already the lowest it can go. 

Gas Price - you can change this. 1 gwei is the lowest and could take up to an hour or two during high traffic periods. The higher the gas fee the faster your transaction will be processed on the blockchain. If you select a low gas fee you may have to wait up to 24 hours before the transaction is processed and stored on the blockchain if the network has a lot of traffic. You can find out more about gas fees by using ethgasstation.info.

Fees from Mintable:

Free for basic smart contract that does NOT use our API or Batch Minting.

$2 to be able to use our API an unlimited number of times.

Batch Minting is listed on the confirmation page - the price depends on which one you select.

ERC-721 Smart Contract Confirmation Page

Once you have confirmed the details of your smart contract, the number of tokens and how fast you want the transaction processed you are ready to create your contract.

You will get an email confirming the transaction and once processed onto the blockchain your tokens will be available to manage and interact with in Mintable. Remember if you select a low gas fee the transaction may take up to 24 hours before its processed onto the blockchain.


How to sell your ERC-721s or NFTs on OpenSea.io

You’ve almost made it, just one last step. And this step is super easy I promise.

The good news is that Mintable is fully supported on Opensea. This means that any NFT you create using Mintable is listed on Opensea’s exchange right away.

Add your ERC-721 to opensea exchange in seconds

Add your ERC-721 to opensea exchange in seconds

 

All you need to do is click that blue button that says - "Sell on OpenSea" then you will be taken to OpenSea to sell it.

To do this you will need to create an OpenSea account, connect with Meta Mask and connect your wallet - thats it!

Congrats, you made it. Now that was long but hey, now you have your own Smart Contract and NFTs and you can start selling things like the pros.

If you have any feedback about Mintable, if anything is not clear, or if you need help let us know.

Also if you have an idea for an NFT and your not sure how to set it up get in our discord and we can help.

If you are looking to make your own NFT smart contract by coding it yourself - there are great courses over at Zastrin.com on making ERC-721 smart contracts with Solidity.

 

 

List of Ideas to tokenize on Mintable

1. Twitch supporter badges for donating

Twitch Supporter NFT that can be bought for Crypto - super rare only 100 going out!!

Twitch Supporter NFT that can be bought for Crypto - super rare only 100 going out!!

For: Anyone with a following on a streaming platform 

If you want to offer a way for your supporters to buy and sell your special Badges you can! You can mint as many tokens as you'd like, have special ones or rare ones and sell them for fixed prices. If your popular enough - maybe people will trade them. You can also use it as a way to get donations - by checking the users Mintable profile you can grant them supporter role in your channel if they verified their twitch username on Mintable!

Example:

Token Name: Exclusive Supporter badge for PewdiePie
Symbol: PDP
URL: Use our API
Metadata: 
Title: Exclusive Supporter badge for PewdiePie
Name: Supporter badge for PewdiePie
Description: Exclusive Supporter badge for PewdiePie - if you donate by buying this 
badge with crypto you will get exclusive access to my content! 
There are only 100 of these made! Get them while they are hot.
URL: Link to channel
Image: Link to the image of the badge
…. You can add up to 20 extra fields so whatever information you want can go here

2. Use tokens to fund a kickstarter type project

Fund a project by using NFTs!

Fund a project by using NFTs!

For: Any entrepreneur who is trying to fund a project 

Now you can tokenize a project and have the decentralized world help fund you. Like a mini-ico. Share details about your project in the contract and then each token is a special form of a donation. Either tokens 1- 100 are super expensive and are for super supporters, or tokens 1-1000 are all common and cheap for anyone. Tokenize shares in a project. Or have levels of tokens for supporters for your project. You can do whatever you want.

Be sure you include your project details and description in the tokens so that users can research before buying.

Tokens could be redeemed once your project is finished for VIP access, game items, you name it! 

Example:

Token Name: My VR video game project
Symbol: VR campaign
URL: Use our API
Metadata: 
Title: The best VR game in the world 
Name: Donate to fund the Best VR game in the world 
Description: This particular token will ost 100$ and will give you VIP
access and new gear inside the best VR game in the world when its released.
URL: Link to your project and more info
Image: link to a cool image
…. You can add up to 20 extra fields so whatever information you want can go here

3. Discounts/Coupons for your business

Sell discounts as ERC-721 tokens to earn crypto for your business

Sell discounts as ERC-721 tokens to earn crypto for your business

For: Any business 

If you own a business you could sell discount cards on Opensea and anyone who owns those cards can use them to be redeemed at your store. For example - if you mint a card with 10% off discount - you then give it away or post it for sale (maybe it has "free item" or something of value instead of 10%).

Once a user buys it - they can simply send it back to your address and when you receive it you can redeem the card for its value at your business. Either online or in person.

Example:

Token Name: Bobs Bike Store
Symbol: BBS
URL: Use our API
Metadata: 
Title: Free tires with a purchase of a frame
Name: Free tires with a purchase of a frame
Description: This card can be redeemed at bobs bike store for free tires
whenever you purchase a complete frame as well. 
Transfer the token to the address listed on bobsbikestore.com 
to redeem with your order
URL: Link to redeem
Image: Image of coupon
…. You can add up to 20 extra fields so whatever information you want can go here

4. Youtube badges for donating and patreon alternative

Support my channel by buying this rare supporters badge! Only 25 made!

Support my channel by buying this rare supporters badge! Only 25 made!

For: Anyone with a following on a streaming platform 

If you want to offer a way for your supporters to buy and sell your special Badges you can! You can mint as many tokens as you'd like, have special ones or rare ones and sell them for fixed prices. If your popular enough - maybe people will trade them. You can also use it as a way to get donations - by checking the users Mintable profile you can grant them supporter role in your channel if they verified their youtube username on Mintable!

Example:

Token Name: Exclusive Supporter badge for PewdiePie
Symbol: PDP
URL: Use our API
Metadata: 
Title: Exclusive Supporter badge for PewdiePie
Name: Supporter badge for PewdiePie
Description: Exclusive Supporter badge for PewdiePie - if you donate by buying this 
badge with crypto you will get exclusive access to my content! 
There are only 100 of these made! Get them while they are hot.
URL: Link to channel
Image: Link to the image of the badge
…. You can add up to 20 extra fields so whatever information you want can go here

5. Link to a download for public content

Free audiobook on gutenberg.org!

Free audiobook on gutenberg.org!

For: Anyone who wants to share content

If you would like to share a download link in the form of a token (ie: airdrop a PDF or something similar) you can use the metadata with the NFT to include the details of what the content is and why people should look at it. Then the link. This token doesn’t need to be sold — could be given away.

Example:

Token Name: Gutenberg press audiobooks
Symbol: Free books for you!
URL: Use our API
Metadata: 
Title: Free gutenberg press audiobooks
Name: Audiobooks
Description: This is my favorite book by Charles Dickens. You should check it out!
Image: https://image-url-here.com
URL: anything.com
…. You can add up to 20 extra fields so whatever information you want can go here

6. Access to private social media groups or discords

Access to a private group via buying a NFT

Access to a private group via buying a NFT

For: people who have a social media group or private facebook/subreddit

By selling this token - you can look at the user's Mintable profile and see their username on the most common social media platforms like facebook, twitch, twitter, reddit, etc. If the user has bought your token, it can be publically displayed and you can verify they bought it. Then you can grant them acess to any group, private website, private subreddit, private forum, etc.

Example:

Token Name: Access to top crypto traders facebook group
Symbol: TOPCALLZ
URL: Use our API
Metadata: 
Title: Access to top crypto traders facebook group
Name: Access for one month - token 123
Description: This token grants the holder one month access to our private trading group. 
One can be used one time.
URL: Link to your group
Image: Image of the groups logo
…. You can add up to 20 extra fields so whatever information you want can go here

7. Blockchain avatars

Demon NFTs made on Mintable

Demon NFTs made on Mintable

For: Graphic Designers, Content Creators, Artists

If you are a graphic designer or someone artistic, you can tokenize avatars such as profile pictures, or unique avatars that can be displayed on people’s profiles. To increase the chance of selling your unique content make sure it looks cool — it’s yours and not found anywhere else — and most importantly — only make a few of each type to provide rarity!

Example:

Token Name: Demon Avatars by Special Artist
Symbol: Demons
URL: Use our API
Metadata: 
Title: Demon Avatars by Special Artist
Name: Demon Avatars
Description: Demon avatars that can be displayed on your Ethereum address. 
Show off your demon on the inside — with a public ethereum address and token attached! 
Only 100 will be made!
Image: link to your unique content
URL: your-domain.com or anything else
…. You can add up to 20 extra fields so whatever information you want can go here

8. Digital Awards (ie: hackathons or real world events)

Real NFT made on Mintable already!

Real NFT made on Mintable already!

For: Event planners, people hosting events or digital contests

If you are throwing a giveaway, have digital prizes for a hackathon, or are hosting a crypto event — you can tokenize any of these things as either awards for prizes from winning something such as a giveaway. Or if you are an event you sell tickets to the event as an NFT

Example:

Token Name: 0x Hackathon Award 
Symbol: 0x
URL: Use our API
Metadata: 
Title: 0x Hackathon Award 
Name: 1St place award!
Description: Congrats on winning 1st place! Enjoy your prize! 
Image: image to award picture
URL: Yourwebsite
…. You can add up to 20 extra fields so whatever information you want can go here

read the full list here: https://blog.mintable.app/2019/04/16/20-top-items-to-sell-as-nfts-erc-721-tokens-on-opensea/

 

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