I'm trying to build a payment gateway and I generated address of a contract before deploying it with create2. how to deploy the contract by sending ether to new generated address?

pragma solidity 0.8.14;

contract A{
    receive() payable external{
        set = "hello";
    string public set;
    constructor() payable {
        set = "world";


contract B{

    event deploy(address addr);
    function Deploy(uint _salt) external{
        A me = new A{salt: bytes32(_salt)}();
        emit deploy(address(me));

    function getaddress(uint _salt) public view returns(address){
    bytes32 hash = keccak256(abi.encodePacked(bytes1(0xFF),address(this),_salt , keccak256(getBytecode(msg.sender))));
    return address(uint160(uint(hash)));

    function getBytecode(address _owner) public pure returns(bytes memory){
    bytes memory bytecode = type(A).creationCode;
    return abi.encodePacked(bytecode , abi.encode(_owner));


here is the code. i know the address of contract A before deploying it using getaddress function , i want to send ether to contract A using the calculated address and then contract A deploy and trigger something like emit an event that contract received the funds.

  • 1
    is the contract already deployed? you can deploy with payments by making the constructor payable. you would also be able to send funds to the contract after deployment if it has a payable fallback function and/or payable receive function
    – sola24
    Jun 14, 2022 at 16:06
  • no it's not deployed but i calculated the address and sent it some funds it received the funds but it didn't deploy. i tried payable constructor , fallback and receive functions.
    – Meysam
    Jun 14, 2022 at 16:28
  • ok. just wondering as I wasn't sure where you were at with it. you can send funds to the address in advance of deploying the contract like you said. What I mentioned was just so you could do the same at deployment time and subsequently if more convenient. I don't understand what you mean by it received the funds but didn't deploy. The contract didn't deploy? Could you clarify what you mean and post the errors/output you get when the contract fails to deploy? Is this on a localhost blockchain / testnet / mainnet? The more info the better
    – sola24
    Jun 14, 2022 at 20:45
  • i edited the question
    – Meysam
    Jun 15, 2022 at 10:16

1 Answer 1


based on your latest comment ... there are a few moving parts and choices / ways to skin the cat, but ...

you'd want to monitor the predetermined addresses off-chain and could use a node like alchemy + javascript + ethers to check the predetermined addresses for non-zero balances. When a non-zero balance is found your deploy script is called passing the target address to deploy to.

here's some rough demo code that checks addresses for a balance. uses: nodejs, ethers, dotenv (just for the alchemy URL)

// todo: schedule this task or loop on timer or something

const NODE_URL = process.env.NODE_URL
var ethers = require('ethers');
var url = NODE_URL;
var provider = new ethers.providers.JsonRpcProvider(url);

const TARGET_ADDRESS1 = "0x3C283D39436c8F5B48E84740e938C745a45c2Ab1";
const TARGET_ADDRESS2 = "0x0eE4A43F8E4eaf59886E1118f61c919F9815f59B";
const TARGET_ADDRESS3 = "0x97ed92E744C10FdD5D403A756239C4069e415e79";

for(let address of addresses) getBalance(address);

async function getBalance(address) {
    const balance = await provider.getBalance(address);
    console.log(`balance at ${address}: ${balance}`);

    if(balance > 0) {
        console.log(`deploying contract to : ${address}`)
        // pseudo code
        // run deploy script passing deployment address


$ node monitor.js
balance at 0x3C283D39436c8F5B48E84740e938C745a45c2Ab1: 0
balance at 0x0eE4A43F8E4eaf59886E1118f61c919F9815f59B: 0
balance at 0x97ed92E744C10FdD5D403A756239C4069e415e79: 80000000000000000
deploying contract to : 0x97ed92E744C10FdD5D403A756239C4069e415e79
  • i know how event works but my problem is i want if someone send ether to contract A then the contract deploys i dont want to deploy it before sending ether. i want to the deploying process be automatic
    – Meysam
    Jun 15, 2022 at 11:35

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