I create my own erc20 token and transfer into the metamask. Now I want to use for purchase things which i am listing on the website .For example ,i made a shop where different things are avaliable . so how i would purchase with my own erc20 token

  • Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer.
    – Community Bot
    Sep 23, 2023 at 13:13

1 Answer 1


Create a Solidity smart contract for your shop:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract Shop {
    address public owner;
    IERC20 public erc20Token;

    struct Item {
        uint256 price;
        uint256 stock;

    mapping(uint256 => Item) public items;

    event Purchase(address indexed buyer, uint256 itemId, uint256 quantity);

    constructor(address _tokenAddress) {
        owner = msg.sender;
        erc20Token = IERC20(_tokenAddress);
        // Initialize items with prices and stock
        items[1] = Item(10 ether, 10);
        items[2] = Item(5 ether, 20);

    function purchase(uint256 itemId, uint256 quantity) external {
        require(quantity > 0, "Quantity must be greater than zero");
        require(items[itemId].stock >= quantity, "Not enough stock");
        uint256 totalPrice = items[itemId].price * quantity;
        require(erc20Token.allowance(msg.sender, address(this)) >= totalPrice, "Not enough allowance");
        require(erc20Token.transferFrom(msg.sender, owner, totalPrice), "Transfer failed");
        items[itemId].stock -= quantity;
        emit Purchase(msg.sender, itemId, quantity);

Frontend Integration: In your website's JavaScript code, you can interact with the smart contract using Web3.js. You'll need to initialize a Web3 provider (like MetaMask) and use it to send transactions. Below is a simplified example:

// Initialize Web3.js with MetaMask or another provider
const web3 = new Web3(window.ethereum);

// Contract address and ABI
const contractAddress = 'YOUR_CONTRACT_ADDRESS';
const contractABI = [...]; // Insert your contract's ABI here

// Create a contract instance
const shopContract = new web3.eth.Contract(contractABI, contractAddress);

// Function to handle a purchase
async function purchaseItem(itemId, quantity) {
    try {
        const accounts = await ethereum.request({ method: 'eth_requestAccounts' });
        const account = accounts[0];
        const gas = await shopContract.methods.purchase(itemId, quantity).estimateGas({ from: account });
        const result = await shopContract.methods.purchase(itemId, quantity).send({
            from: account,
        console.log('Purchase successful:', result);
    } catch (error) {
        console.error('Purchase error:', error);
  • Can it deploy on sepolia or localhost? To use own Erc20 token
    – Rizwan Ali
    Sep 20, 2023 at 7:48
  • Yes, you can deploy and test on any network, mainnet or local
    – Mehran Ra
    Sep 20, 2023 at 10:54

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