As it's not been minted yet, it doesn't exist, right?

However, what if I had an idea to create a future collection of 333 NFT. And I wanted to allow certain users to mint certain NFTs. Meaning, future ones.

Would this be possible? Could I refer to an id-s of the NFTs that haven't been minted yet, to create a mapping, and would this work?

    mapping(uint => address) private _nftsUsersWhiteList;
    //mapping(uint => address[]) private _nftsUsersWhiteList;

Would there be downsides?

Both ERC721 and ERC1155

1 Answer 1


Yes, you can make a whitelist contract and have users join the whitelist before you launch your NFT collection. The whitelist contract can look something like this:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

import "@openzeppelin/contracts/access/Ownable.sol";

error TransactionFailed();
error SpendMoreETH();

 * @title Whitelist
 * @dev A contract that manages a whitelist of addresses.
contract Whitelist is Ownable {
  address[] private _whitelisted;
  uint256 public immutable WHITELIST_FEES = 1274577610908013100; // about 1.3 ETH

  event Whitelist__Joined(address indexed);

   * @dev Allows an address to join the whitelist by paying the required fees.
   * Emits a Whitelist__Joined event upon successful registration.
  function joinWhitelist() public payable {
    if (msg.value <= WHITELIST_FEES) {
      revert SpendMoreETH();

    emit Whitelist__Joined(msg.sender);

   * @dev Allows the owner to withdraw the contract's balance.
   * Emits a TransactionFailed error if the withdrawal fails.
  function withdraw() public onlyOwner {
    address receiver = msg.sender;
    (bool sent, ) = receiver.call{value: address(this).balance}("");
    if (sent != true) {
      revert TransactionFailed();

   * @dev Checks if an address is whitelisted.
   * @param _addr The address to check.
   * @return A boolean value indicating whether the address is whitelisted.
  function isWhitelisted(address _addr) public view returns (bool) {
    for (uint i = 0; i < _whitelisted.length; i++) {
      if (_whitelisted[i] == _addr) {
        return true;
    return false;

Later, in your NFT contract you can access the whitelisted members and do some action (discounts / rewards). Your mint function could look something like this:

function mintNft() public payable returns (uint256 requestId) {
            // do something
  • wrong. re-read my question
    – DankenN
    Jun 8, 2023 at 11:33

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