Is it possible to make 2 transactions at once?

Question

I heard that it is possible to make multiple transactions like, "send eth to account b" and then instantly "send tokens from account b to a" in one batch.

I don't know how I would do that though, does anyone know how to achieve this?

Thanks!

Answer 1

you can use smart contract for that.

interface IERC20{ 
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
}


contract Contract {
    // this requires B to approve amount to the Contract from token address and A calls this function
    function oneTransaction(address token, address B, address A, uint256 amount) external payable {
         (bool sent, bytes memory data) = B.call{value: msg.value}("");
        require(sent, "Failed to send Ether");

        IERC20(token).transferFrom(B, A, amount);
    }
}

Answer 2

If there is a function in b that on receiving funds immediately sends them to a, it is possible. That would be one transaction.