Contract Library Addresses for Etherscan verification

I am trying to insert the .sol file in the contract displayed in Robsten net. Buy I need the address of librarys and contracts. Is my first contract in this tecnology.

:computer: Environment

Testnet Robsten contract:

:1234: Code to reproduce

//Contract based on

// SPDX-License-Identifier: MIT

// In memory of my dear dog Estrella. Rest in peace 2021 - April

pragma solidity ^0.7.3;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

import "@openzeppelin/contracts/utils/Counters.sol";

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

contract NFT is ERC721, Ownable {

    using Counters for Counters.Counter;

    Counters.Counter private _tokenIds;

    constructor() public ERC721("NFT", "NFT") {}

    function mintNFT(address recipient, string memory tokenURI)

        public onlyOwner

        returns (uint256)



        uint256 newItemId = _tokenIds.current();

        _mint(recipient, newItemId);

        _setTokenURI(newItemId, tokenURI);

        return newItemId;



Hi there. No library addresses are needed in this case. For verifying the contract I would recommend deploying using Hardhat and verifying using the hardhat-etherscan plugin. Do not deploy to mainnet until you have successfully verified the contract on a testnet.

Hello It has been done with Hardhat. But when uploading the contract to the network, robsten asks you for the separate files. And I don’t think I have to upload the JSON and Javascript Scripts there, right?

Only .sol not?

If you deployed with hardhat then just use the hardhat-etherscan plugin! You don’t need to interact with the Etherscan site. Please take a look at the documentation for the plugin:

Very interesting this plugin. But I already have the contract deployed. Excuse my newbie ignorance, but can I still include the plugin yet?

Yes, just run the command shown in the documentation:

npx hardhat verify --network mainnet DEPLOYED_CONTRACT_ADDRESS "Constructor argument 1"

I must introduce robsten in mainet and my two constructor arguments. like this ?:

npx hardhat verify --network robsten DEPLOYED_CONTRACT_ADDRESS "NFT, NFT"

I receive the following message and I do not verify that the contract is validated on the network

Error HH100: Network robsten doesn't exist

Dependecies installed ok

I think I have installed everything correctly

A typo, ropsten rather than robsten

My eternal problem between b and p. Will it be the fault of being Spanish? thanks for your time

Hi, how can I verify contract using Hardhat on Cronos net?
I found that it's difficult to use hardhat-etherscan plugin for contract verify in cronos network.

Please refer to our guide on verification: