Customize the NFT template

Change the NFT template’s price, supply, artwork and mint rules, then redeploy it as your own collection.

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 UzoNFT. The settings change without code. The artwork, traits, wallet limits and royalties each need a small contract change. Pick the ones you need.

Prerequisites

A copy of the template that deploys, from Use a template.
The walkthrough, so you know how tokenURI builds the art.

Name, price and supply

Set these in .env and deploy again:

.env

NFT_NAME="My Collection"
NFT_SYMBOL=MYC
NFT_MINT_PRICE=0.05
NFT_MAX_SUPPLY=500

NFT_MINT_PRICE is in BOT. The deploy script converts it to wei and passes it to Foundry as NFT_MINT_PRICE_WEI, so you don’t set that yourself. For a free mint, use NFT_MINT_PRICE=0. NFT_MAX_SUPPLY can’t change after deploy. The owner can change the price at any time with setMintPrice.

Change the contract

Edit the contract

Artwork
More traits
Limit per wallet
Royalties

Edit _svg in contracts/UzoNFT.sol. It receives the token ID and its hue and returns an SVG string.

Use single quotes inside the SVG. The SVG sits inside a JSON string, and double quotes would break it.
Keep it small. Every byte adds to the deploy cost.
If you need a different colour per token, reuse _hue, which gives the same ID the same hue every time.

Add entries to the attributes array in tokenURI. Each entry is a {"trait_type":"...","value":...} object. Keep the commas between entries, because the contract builds the JSON by joining strings.

Count mints per address and check the count in mint():

contracts/UzoNFT.sol

uint256 public constant MAX_PER_WALLET = 3;
mapping(address => uint256) public minted;

error WalletLimitReached();

function mint() external payable nonReentrant returns (uint256 tokenId) {
    if (msg.value != mintPrice) revert WrongPayment(msg.value, mintPrice);
    uint256 supply = totalSupply();
    if (supply >= maxSupply) revert SoldOut();
    if (minted[msg.sender] >= MAX_PER_WALLET) revert WalletLimitReached();
    minted[msg.sender] += 1;

    tokenId = supply + 1;
    emit Minted(msg.sender, tokenId);
    _safeMint(msg.sender, tokenId);
}

A limit per address slows down one wallet, but anyone can create more addresses.

Add OpenZeppelin’s ERC2981, which tells marketplaces what royalty you ask for:

contracts/UzoNFT.sol

import {ERC2981} from "@openzeppelin/contracts/token/common/ERC2981.sol";

contract UzoNFT is ERC721, ERC721Enumerable, ERC2981, Ownable, ReentrancyGuard {
    // In the constructor, after maxSupply = maxSupply_;
    //     _setDefaultRoyalty(owner_, 500); // 500 basis points is 5%

    function supportsInterface(bytes4 interfaceId)
        public
        view
        override(ERC721, ERC721Enumerable, ERC2981)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
}

Replace the existing supportsInterface with this one. ERC-2981 only reports the royalty. Each marketplace decides whether to pay it.

Run the tests

Terminal

npm test
npm run test:hardhat

The tests decode the JSON and SVG from tokenURI, so a broken quote in your artwork shows up here. Add tests for any new rule, such as a fourth mint from one wallet reverting.

Refresh the ABI

Terminal

npm run abi

This rewrites frontend/src/abi.ts, so the web app knows about new functions and errors.

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 for colours and fonts, and frontend/src/styles.css for styles that belong only to this app.

Hand over ownership

The owner sets the price and receives withdrawals. To hand that to a multisig, call transferOwnership(newOwner) from the owner wallet. The new owner receives all future withdrawals.

Terminal

cast send <nft 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

Mint one token from the web app and check the gallery shows your new art. On BOTScan, open the token’s page and check its image and attributes. If you added royalties, call royaltyInfo(1, 10000) on the Read contract tab. It should return the owner and 500.

Troubleshooting

Tests fail to decode the JSON after I changed the artwork

A double quote inside the SVG ends the JSON string early. Use single quotes for every SVG attribute.

WrongPayment when minting

You must send exactly mintPrice. The owner may have changed it since the page loaded. Reload and try again.

Compiler error about supportsInterface or _update

Each parent that defines the function must appear in the override(...) list. With ERC2981 added, supportsInterface needs all three.

I want to charge USDT instead of BOT

USDT on BOT Chain has 6 decimals, so use parseUnits(amount, 6), never parseEther, and move it with OpenZeppelin’s SafeERC20. See USDT and decimals.

Overview

Templates

Contributing

Customize the NFT template

What you’ll build

Prerequisites

Name, price and supply

Change the contract

Change the look

Hand over ownership

Verify

Troubleshooting

Next steps

Gasless app template

Events without getLogs

​What you’ll build

​Prerequisites

​Name, price and supply

​Change the contract

​Change the look

​Hand over ownership

​Verify

​Troubleshooting

​Next steps

Gasless app template

Events without getLogs

What you’ll build

Prerequisites

Name, price and supply

Change the contract

Change the look

Hand over ownership

Verify

Troubleshooting

Next steps