Create an ERC-20 Token Using Solidity

ERC-20 tokens are the most fundamental and essential concept in Ethereum. As the Metal Blockchain community and the ecosystem are growing, new use cases and projects that are running on Ethereum or different chains would be implemented to Metal Blockchain.

Therefore, we will be creating our own mintable ERC-20 token and will mint it to any address we want. The token will be generated on Metal C-Chain and will be accessible on that chain. We are using Tahoe Testnet in this tutorial.

The article focuses on deploying a smart contract written with Solidity to Metal Blockchain. This is the feature that Metal Blockchain provides us - to be able to deploy any smart contract to the chain and no requirement for a new language specific contract concept to interact. Let’s look at how to create an ERC-20 contract and deploy it to Metal Tahoe C-Chain on testnet.

Set up MetaMask and other wallets automatically

You can easily add the Metal Blockchain network to an Ethereum wallet by visiting Chainlist and clicking on the "Connect Wallet" button under the Metal C-Chain option. For this guide we use the Tahoe testnet.

Set up MetaMask manually

The first thing we should set is a MetaMask wallet.

Click to MetaMask icon on the browser and select the network drop-down menu. Here we should connect to C-Chain. Click to "Add Network".

Now, we need to set these boxes with correct values.

Metal Blockchain Mainnet Settings:

• Network Name: Metal C-Chain
• New RPC URL: https://api.metalblockchain.org/ext/bc/C/rpc
• ChainID: 381931
• Symbol: METAL
• Explorer: https://metalscan.io/

Metal Blockchain Tahoe Testnet Settings:

• Network Name: Metal Tahoe C-Chain
• New RPC URL: https://tahoe.metalblockchain.org/ext/bc/C/rpc
• ChainID: 381932
• Symbol: METAL
• Explorer: https://tahoe.metalscan.io/

Fund Your C-Chain Address

For funding on the Tahoe Testnet, you can use the Test Network Faucet. Navigate to https://faucet.metalblockchain.org/ and paste your C-Chain address.

Create Mintable Token

Now, we can create our mintable token on Remix. Open Remix on your browser or go to this link.

You should view this page. On this page, first, click "SOLIDITY" from "Featured Plugins" and then click the "New File" button. When you click the New File button, you will see a pop-up that requires a file name. You can choose a name or leave the default.

Since we will use an ERC-20 contract from OpenZeppelin, just paste this line to the file and save.

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/presets/ERC20PresetMinterPauser.sol";

After saving the file, we will see a bunch of files that are imported to remix. This is a remix feature that allows us to import a GitHub contract repository to remix by just giving the URL-link with an import statement.

We have ERC20PresetMinterPauser.sol file in the presets. This file is written by OpenZeppelin according to ERC20 standards with minter functionality. After deploying this file, we will be the owner of the contract and thus have the authority and ability to mint the tokens.

Deploy the Contract

Open the tab with label Solidity compiler and select the solidity version that matches with the solidity version written in file as pragma solidity …... The version should be equal to or higher than the file’s version. For example, in my file, pragma solidity ^0.6.0 is written so the required version is 0.6.0 or higher. As shown, in the compiler the solidity version is 0.6.6, which is OK. After checking the solidity version click the compile button. If you did not change anything in the file, or the solidity version is not wrong, the contract should compile without any errors.

Then, let’s jump to the tab with label Deploy & run transactions. Here before deploying our contract, we should change the environment. Click to the environment and select "Injected Web3." If a pop-up shows up and asks you to connect the account, click to connect. After, you should see the account address in the "ACCOUNT" text box.

The last thing before the deployment process is to set the contract that will be deployed as a token. Above the Deploy Button, there is a drop-down menu to select a contract. Select the contract named ERC20PresetMinterPauser.sol.

Now, here enter the name and symbol of your token. I will name it "MetalBlockchainTest" and the symbol will be MBT. Click on the transact button to proceed.

After clicking the button, a pop-up will show up and just confirm it.

And then another pop-up, a MetaMask confirmation, appears. Confirm it.

After confirming all these pop-ups we have deployed our token to Metal Tahoe C-Chain on testnet. So we can start to interact with it.

Interact with Token

We can see our transaction that deployed on Metal C-Chain via the C-Chain explorer.

But firstly, let’s see our transaction hash from the remix console.

After deploying the contract, we should see a log in the remix console. When you click to arrow and expand it, a transaction hash will come up. Copy it.

Just paste the transaction hash to the explorer in the search bar and press enter.

Here we can see all details about the transaction and token contract.

The first one is my wallet address that creates token and the second address is my token contract address which is named MetalBlockchainTest. Now, let’s mint some token to our own address.

Come back to the remix console and after deploying, you should be able to see the contract in "Deployed Contracts" section.

Here, we have a bunch of functions that we can use to interact with our token contract. You can check all these methods from OpenZeppelin documentation to learn how to use them. But we will only use the mint method.

Click the arrow beside the mint method to read it.

Enter your address and an amount in wei. For example, I will mint 1000 MBT token so, I entered "1000000000000000000000"

Add Token to MetaMask

Now we minted 1000 token to our contract, but you should not be able to see the tokens in your MetaMask wallet. In order to see our own token, we have to add it. On MetaMask, click on the "Import Token" option.

Here enter the token address that you can see from explorer as I showed above. Copy and paste it here. It should automatically add the token symbol and decimal. Then click on the Next button, you should see 1000 token that you named in your MetaMask wallet. Also, you can send it to another account via either remix or MetaMask.