Verify smart contracts manually

This page outlines the steps for verifying contracts on Neon EVM manually on NeonScan and Blockscout.

Before beginning the tutorial below, please follow this page which describes how to deploy a smart contract on Neon EVM using Remix IDE.

If you are not using Hardhat or Foundry tools for deployment and using Remix for the smart contract development, then you can verify your smart contracts on NeonScan or Blockscout.

Step 1: Deploy the contract

For this example, let us take a simple smart contract TestERC20.sol -

// SPDX-License-Identifier: MIT
pragma solidity 0.8.24;

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

contract TestERC20Manual is ERC20 {
    constructor() ERC20("TestERC20", "TST") {
        _mint(msg.sender, 1000 * 10 ** decimals());
    }
}

Step 2: Verify the deployed contract

If your smart contract references different solidity files in its imports, you can upload a flattened version of the smart contract or upload each solidity file your smart contract references.

To flatten your contract, right-click the filename on your Remix.IDE file explorer, and choose flatten. Remix.IDE will generate a flattened version of your smart contract e.g., TestERC20_flattened.sol in this case, that you can paste into NeonScan or Blockscout.

NeonScan

To verify the deployed contract from the above step, let's take an example of a deployed contract with address 0x628C8F52De7C661AA703523eDD75539Dce8D7EBB on Neon EVM Devnet.

The deployed contract can be found here https://devnet.neonscan.org/address/0x628C8F52De7C661AA703523eDD75539Dce8D7EBB#contract.

1. Click on the Verify Contract Code link to go the verification page.

2. On the Verify and Publish page, the Contract Address field is auto-filled with the deployed contract address.

3. Enter the name of the deployed contract in the Contract Name field. In this example, the name of the deployed contract is TestERC20Manual.

4. Select the Compiler Type from the dropdown. In this example, this should be Solidity.

5. Select the Compiler Version from the dropdown. In this example, the compiler version used is v0.8.23+commit.f704f362.

6. Select Optimization from the dropdown and the Run value. In this example, optimization is Yes and the value is 200.

7. Enter the name of the flattened smart contract in the File name field and the flattened solidity source code in the Code field. The file name in this example is TestERC2_flattened.sol.

8. After clicking on the Submit button, the verified contract source code can be seen on the contract page https://devnet.neonscan.org/address/0x628C8F52De7C661AA703523eDD75539Dce8D7EBB#contract.

Blockscout

To verify the deployed contract from the above step, let's take an example of a deployed contract with address 0x00407307F5eb91dFCC406E88618dB8aAE7d715B8 on Neon EVM Devnet.

The deployed contract can be found here https://neon-devnet.blockscout.com/address/0x00407307F5eb91dFCC406E88618dB8aAE7d715B8?tab=contract.

1. Click on Verify & publish.

2. On the Verify & publish page, choose Contract license from the dropdown. In this example, the license mentioned in the smart contract is MIT.

3. Choose verification method or compiler type from the dropdown. In this example, we are using Solidity (Flattened source code).

4. Choose compiler and the EVM version from the dropdowns. These fields should be entered as per the configuration in Remix IDE. In this example, we are using compiler 0.8.24+commit.e11b9ed9 and EVM version default.

5. Click on the Optimization enabled if it is enabled in Remix IDE. Enter the flattened solidity code in the Contract code box.

6. After clicking on the Verify & publish button, the verified contract source code can be seen on the contract page https://neon-devnet.blockscout.com/address/0x00407307F5eb91dFCC406E88618dB8aAE7d715B8?tab=contract.