How to deploy a Smart Contract to the Testnet

In this article I will teach you how to deploy your contract to the Rinkeby Testnet.

To be faster we will use our project from another article: How to create a smart contract to mint an nft

Creating an account and an Ethereum project in Infura

Infura provides instant access over HTTPS and WebSockets to the Ethereum network.

Access Infura

1. Create your account (Common Steps).
2. Click Ethereum, then create new project.

1. Give a name for your project .
2. Save your project id.

Initial settings

Returning to the project, let's make the initial settings for our project.

Let's go to the hardhat.config.js file and add an object called network along with another object called rinkeby containing url and accounts.

require("@nomiclabs/hardhat-waffle");

/**
 * @type import('hardhat/config').HardhatUserConfig
 */

module.exports = {
  solidity: "0.8.3",
  networks: {
   rinkeby: {
     url: "", //Infura url with projectId
     accounts: [""] // add the account that will deploy the contract (private key)
    },
  }
};

Now in url we add the url with the project id provided by Infura and in accounts we add the private address of our wallet.

Note: Be careful with your private key, it gives access to your wallet and will spend its crypto to deploy the contract.

require("@nomiclabs/hardhat-waffle");

/**
 * @type import('hardhat/config').HardhatUserConfig
 */

module.exports = {
  solidity: "0.8.3",
  networks: {
   rinkeby: {
     url: "https://rinkeby.infura.io/v3/ba900937b83f4883b926713999277b1f", //Infura url with projectId
     accounts: ["123456789101112131415"] // add the account that will deploy the contract (private key)
    },
  }
};

Creating the script to deploy

Now to deploy the smart contract to rinkeby testnet, we are going to make a script with the hardhat that will make it easier for us to upload it with a command.

In the root directory, create a folder called scripts and inside a file called deploy.js

/node_modules
/contracts
/test
/scripts
 | - deploy.js
hardhat.config.js
package.json
yarn.lock

Now we're going to modify the file by adding the script below, where I'll explain it line by line.

deploy.js

const hre = require("hardhat"); //import the hardhat

async function main() {
  const [deployer] = await ethers.getSigners(); //get the account to deploy the contract

  console.log("Deploying contracts with the account:", deployer.address); 

  const FactoryNFT = await hre.ethers.getContractFactory("FactoryNFT"); // Getting the Contract
  const factoryNFT = await FactoryNFT.deploy(); //deploying the contract

  await factoryNFT.deployed(); // waiting for the contract to be deployed

  console.log("FactoryNFT deployed to:", factoryNFT.address); // Returning the contract address on the rinkeby
}

main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  }); // Calling the function to deploy the contract 

Now to deploy your contract just run this commands:

yarn compile 

yarn hardhat run scripts/deploy.js --network rinkeby

result

Deploying contracts with the account: 0xAFEeb469Ce6376979Ea037b4CE6b7172f9018007
FactoryNFT deployed to: 0xF9e6b75cE8da147D4f1d7d2cc597A7A42A645006

Contract deployed!!!

Now you can Follow me on: Twitter
Project Repository: https://github.com/EmanuelCampos/mint-nft/tree/with-deploy-config

Comments

[Leonardo Mocaiber]

Hi, When I try run the compile I'm receiver a error:
"Error HH8: There's one or more errors in your config file:

• Invalid account: #0 for network: rinkeby - private key too short, expected 32 bytes To learn more about Hardhat's configuration, please go to hardhat.org/config/" Like the url rinkeby dont exist and when I'm try open the rinkeby url return 404. Any tips that can help me out? Thanks, congratulations great article.

[Emanuel Ferreira]

Hey, are you using the correct private key of your wallet? it's not your address, but your private key

[Gitatron Maximus]

I had the error like this:

Error HH8: There's one or more errors in your config file:

• Invalid account: #1 for network: sepolia - private key too long, expected 32 bytes To learn more about Hardhat's configuration, please go to hardhat.org/config/

//Turns out I put a space after the comma when I was listing the accounts. I took the space out and the error resolved.

[Matthew Eller]

NGL, I ran into this issue and it took me a few minutes to realize that I was calling the run scripts from the wrong directory...

[Atang]

Save the private key in full with 0x prefix as an environment variable and then pass it in with the method .toString().

process.env.PRIVATE_KEY.toString()

[Nikola]

Hi !
I got `The Solidity version pragma statement in these files doesn't match any of the configured compilers in your config. Change the pragma or configure additional compiler versions in your hardhat config.

• contracts/factoryNFT.sol (^0.8.3)
• @openzeppelin/contracts/token/ERC721/ERC721.sol (^0.8.0)` etc...

Any suggestion ?

[Saurabh Bomble]

Hey @emanuelferreira , great article.
I am getting an error while deploying to the ropsten network

"Cannot read properties of null (reading 'sendTransaction')"

I have used private key exported from metamask as you asked. I could use some help.

[yang]

Thanks. What is rinkeby.accouts? "in accounts we add the private address of our wallet." I don't know it is an address or a key? If is private key, how does it transfer to rinkeby? Is there a leak risk?

[Emanuel Ferreira]

The private key, to deploy the contract using your address/wallet

[cocafe.crypto]

Hi,

I got the error "Error HH100: Network rinkeby doesn't exist" when running the command to deploy the contract.

What can I do to fix this error?

[Zaigam Akhtar]

I got the same error. Somebody please reply?

[Keijo Keijonen]

what is yarn compile

[Emanuel Ferreira]

Yarn compile is a script of hardhat to compile the smart contract.
in the package.json file you can add a script called compile with this command:
yarn hardhat compile