Customize the Token template

Change the token template’s name, supply rules and look, then redeploy it as your own token.

Ready. This template is published in uzolabs/templates and has been deployed and verified on testnet. It’s a learning template and hasn’t been audited. Use test funds only.

What you’ll build

Your own version of UzoToken: a new name and supply, and optionally a fixed supply, burning or a hard cap. Each change below is independent, so pick the ones you need.

Prerequisites

A copy of the template that deploys, from Use a template.
The walkthrough, so you know which file does what.

Name, symbol and supply

These need no code changes. Set them in .env and deploy again:

.env

TOKEN_NAME="My Token"
TOKEN_SYMBOL=MYT
TOKEN_INITIAL_SUPPLY=500000

TOKEN_INITIAL_SUPPLY is in whole tokens. The deploy script converts it to the smallest unit for you. Each deploy creates a new contract. The old one stays on chain.

Change the contract

Edit the contract

Pick one or more of the changes in the tabs.

Burnable
Capped
Fixed supply
Decimals

Add OpenZeppelin’s ERC20Burnable, so holders can destroy their own tokens.

contracts/UzoToken.sol

import {ERC20Burnable} from "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";

contract UzoToken is ERC20, ERC20Burnable, ERC20Permit, Ownable {
    // constructor and mint unchanged
}

Use ERC20Capped so mint can never push the supply past a limit. Because ERC20Capped overrides _update, you must override it too.

contracts/UzoToken.sol

import {ERC20Capped} from "@openzeppelin/contracts/token/ERC20/extensions/ERC20Capped.sol";

contract UzoToken is ERC20, ERC20Capped, ERC20Permit, Ownable {
    constructor(string memory name_, string memory symbol_, uint256 initialSupply, address owner_)
        ERC20(name_, symbol_)
        ERC20Capped(10_000_000 ether)
        ERC20Permit(name_)
        Ownable(owner_)
    {
        _mint(owner_, initialSupply);
    }

    function mint(address to, uint256 amount) external onlyOwner {
        _mint(to, amount);
    }

    function _update(address from, address to, uint256 value)
        internal
        override(ERC20, ERC20Capped)
    {
        super._update(from, to, value);
    }
}

10_000_000 ether means 10 million tokens with 18 decimals. The ether suffix only multiplies by 10^18; it has nothing to do with BOT.

Remove mint so nobody can create more tokens after deploy:

Delete the mint function and Ownable from contracts/UzoToken.sol.
Remove the owner argument from the constructor, script/Deploy.s.sol, ignition/modules/UzoToken.ts and scripts/deploy.ts.
Delete the mint tests in test/UzoToken.t.sol.

Override decimals() to use something other than 18:

contracts/UzoToken.sol

function decimals() public pure override returns (uint8) {
    return 6;
}

Amounts in the scripts and web app then scale differently. Check every parseUnits and formatUnits call, and read USDT and decimals.

Run the tests

Terminal

npm test
npm run test:hardhat

Add tests for whatever you changed, such as a test that minting past the cap reverts.

Refresh the ABI

Terminal

npm run abi

This rebuilds the contract and rewrites frontend/src/abi.ts, so the web app can call the new functions.

Deploy and verify

Terminal

npm run deploy
npm run verify

Restart npm run frontend so it reads the new address.

Change the look

Edit the variables at the top of frontend/src/theme.css to change colours. Swap its two @import lines to load your own fonts. Put styles that belong only to your app in frontend/src/styles.css.

Hand over ownership

The deployer owns the token and is the only account that can mint. To give that power to a multisig, call transferOwnership(newOwner) from the owner wallet:

Terminal

cast send <token address> "transferOwnership(address)" <new owner> --rpc-url https://rpc.bohr.life --private-key $PRIVATE_KEY

Load PRIVATE_KEY from your .env into the shell first, for example with source .env, rather than pasting it into the command.

Verify

After deploying, open the BOTScan link from the deploy output. On the Read contract tab, check name, symbol, totalSupply and, if you added one, cap.

Troubleshooting

Compiler error: function needs to specify overridden contracts

Two parents define the same function, usually _update. Add an override that lists both, as in the Capped tab.

The web app doesn't show my new function

Run npm run abi after changing the contract, then restart npm run frontend.

Hardhat verify fails after I changed the constructor

scripts/verify.ts passes the arguments saved in deployments/968.json. Update scripts/deploy.ts and the Ignition module so they save and pass your new arguments.

Overview

Templates

Contributing

Customize the Token template

What you’ll build

Prerequisites

Name, symbol and supply

Change the contract

Change the look

Hand over ownership

Verify

Troubleshooting

Next steps

NFT template

Add liquidity

​What you’ll build

​Prerequisites

​Name, symbol and supply

​Change the contract

​Change the look

​Hand over ownership

​Verify

​Troubleshooting

​Next steps

NFT template

Add liquidity

What you’ll build

Prerequisites

Name, symbol and supply

Change the contract

Change the look

Hand over ownership

Verify

Troubleshooting

Next steps