In this step-by-step tutorial you will learn how to issue and play with your own ERC-20 token on Ethereum. This tutorial can be completed by people with no blockchain programming experience and novice programmers.
We will use Metamask and Remix IDE
By the end of this tutorial you will be able to deploy standard ERC-20 Tokens! Please get your code verified and audited by a 3rd party before releasing any token to the public.
Download and Install MetaMask
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Install on Chrome, Firefox or Brave Browser
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Create a new account and save your 12 word mnemonic
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Select a test network. The Ropsten Network should work fine.
Get Some Testnet Ether
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Click "Buy" or "Deposit" on Metamask or go to the Metamask Faucet
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Hit "Send Me Ether". It should not take long (10-20 seconds)
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Double check Ether was received by hitting the MetaMask Icon
Find Source Code for a Standard ERC-20 Smart Contract. You want a well tested open source implementation such as the official Consensys or Open Zeppelin implementation. Select one of the following two options:
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Navigate to the Consensys Token Repository.
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Navigate to the [OpenZeppelin Smart Contract Repository] (https://github.com/OpenZeppelin/openzeppelin-contracts/tree/master/contracts). Find
These repositories contain the solidity code you need to deploy your token. Consensys implemntation is easier to deploy, but the OpenZeppelin implementation is more widely used in practice.
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Launch Remix
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Enable the "Solidity Compiler" and "Deploy & Run Transactions" Tabs. Find them using the plugin manager on the left.
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Copy the .sol files you need into remix. To create a new .sol file, click the "+" button in the top left. Either copy the code directly from github, or clone the repository and open the local files.
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For the Consensys implementation get
- EIP20interface.sol
- EIP20.sol
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For the OpenZeppelin implementation get
- ERC20.sol
- IERC20.sol
- SafeMath.sol
- Context.sol
- ERC20Detailed.sol. You will have to locate them in different folders.
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Open the base contract. For Consensys it's EIP20.sol. For OpenZeppelin it's ERC20Detailed.sol
- For the OpenZeppelin contract, import and inherit ERC20.sol instead of IERC20.sol.
import "./ERC20.sol" contract ERC20Detailed is ERC20.sol -
Try compiling the contract by pressing ctrl-s or pressing the compile button on the compile tab. You will notice a couple errors.
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Make sure all import references work. For example import "./SafeMath.sol"
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Make sure the compiler version is the same as the contract version
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Ensure the contract compiles correctly
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Think of a cool name for your token and rename your base file YourTokenName.sol
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rename your contract
contract YourTokenName{
- For the Consensys contract, rename your constructor function from EIP to yourTokenName
```
function YourTokenName(
```
Now you can personalize the token according to your preferences
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Decide on a symbol to go with your name, e.g. YTN for YourTokenName
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Decide on the number of decimal places your token will have.
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Decide on your Token Supply, or how many tokens you want to exist in total.
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NOTE: Ethereum only deals in integers only and DOES NOT recognize fractions. 1000 integers are required to represent 1 token with 3 decimal places. Therefore add an extra 0 to your token supply for every decimal place in your token.
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Click on the Run tab in remix
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Next to the Deploy Button, Enter your InitialAmount, TokenName, Decimals, TokenSymbol as parameters like so: 1000000,"YourTokenName",3,"YTN". Don't forget quotes for the strings.
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Alternatively you can directly input values into your Smart Contract code. Just remember to remove the code that sets the variables inside the constructor function
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Check for errors on remix. Yellow warnings are ok. Red warnings must be fixed before the next step.
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Make sure you are still on the Run tab
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Select YourTokenName in the drop down menu
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Select "Injected Web3" for your environment
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Click Deploy
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Approve the transaction on metamask. You may need to enable pop ups on your browser
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Wait for the transaction to mine! Check for confirmation on EtherScan. You can click on your latest transaction in metamask.
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After the transaction has mined, click the contract address and copy it
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Paste it into the Tokens sectionin Metamask
You have now issued your first Token. Great Work! This is just the tip of the iceberg.
- Gas price should auto update. For live Eth use https://ethgasstation.info/
Now we are going to register this contract. To do this:
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Using Etherscan: In the Overview Tab → Click on the Contract Address
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Go to the Contract Code Tab → Click Verify and Publish
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Be sure that the contract address field corresponds to the contract address that you have just deployed. Remember contract address is different to your public key
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The contract name has to match the one in the code, in my case is this: WaterlooCoin. This will be on Line 102 in your code
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Enter the correct compiler version. At the time of writing, this is
Compiler: 0.4.24+commit.e67f0147In future builds, this can be found by hitting the Details tab under Compile, and selecting the Compiler dropdown under MetaData. -
On Optimisation, choose No (We haven’t enable it before).
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On ENTER THE SOLIDITY CONTRACT CODE BELOW, copy the whole code from Remix, and paste in that area.
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Leave the other fields in blank and click on Verify and Publish.
If you get a success! It worked.
To confirm that it worked, go to https://ropsten.etherscan.io/ and look up your metamask address. Hit the View Tokens dropdown to see if you tokens are in there.
Send some to your neighbours:
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In Metamask Open the menu and click "Add Tokens"
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Click Add Custom Token and Input your Contract Address. Your token details should appear automatically
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You should now see your token balance. Try sending some tokens to your friend's address Check Etherscan for progress
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Your friend can then enter your contract info and code to view your tokens in their wallet!