In this section, we will go over the process of verifying a smart contract in Subscan. Verifying your smart contract allows for readable and interpretable data (such as function calls and parameters) to be displayed directly in Subscan, making it easier to understand and debug interactions with the contract.

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Prerequisites

  • Familiar with Subscan Block Explorers. If not checkout the Block Explorers section.
  • You have previously deployed a smart contract using one of the previous tutorials (e.g. SimpleStorage.sol).

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Instructions

Follow these steps to complete the verification process. We will be showing how this ca:

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1. Go to Remix for content

We will be using the same Remix IDE workspace that was used to deploy the SimpleStorage.sol contract. Once you are there:

  • Open up the artifacts/build-info/hex_value file. This contains the content we need to move to the SimpleStorage_metadata.json file.
  • Copy and paste the entire content line as shown in the screenshot above.

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2. Paste content into SimpleStorage_metadata

After copying this content we will need to paste it into the SimpleStorage_metadata.json file.

  • Navigate to the SimpleStorage_metadata.json file.
  • Find the sources object where the data for contract SimpleStorage.sol is stored.
  • Paste the content after the license field.

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3. Download the SimpleStorage_metadata.json file

The next step is to simply download this file to your local machine. It will be used later in the verification process.

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4. Navigate to Subscan

Now go to Subscan and search for your deployed contract address. Then go to the Contract tab.

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5. Verify Contract

  • Confirm the Contract Address field matched your Smart Contract to verify.
  • Select Solidity (Standard-JSON-Input) as Compiler Type.
  • Pick whether or not you would like to Include Nightly Builds.
  • Choose the Compiler Version that was used when you compiled your smart contract.
  • Upload the file that we downloaded from Remix earlier.
  • Finally, click the Verify & Publish button.

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6. Confirm Verification

A proper Contract Verification will have a ✅ next to Contract.

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Contract Information Displayed

  • Contract Name: SimpleStorage
  • Compiler Version: v0.8.26+commit.8a97fa7a
  • EVM Version: cancun
  • Optimization: false

This indicates the deployed contract was compiled using Solidity version 0.8.26, with the Ethereum Virtual Machine (EVM) set to cancun, and without optimization enabled.

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Contract ABI

  • The ABI (Application Binary Interface) specifies the interface of the contract.
  • It includes the function details such as:
    • Function get:
      • Inputs: None.
      • Outputs: A single uint256 value.
      • Mutability: view (read-only).
    • Function set:
      • Inputs: A single uint256 value (_data).
      • Outputs: None.
      • Mutability: nonpayable (modifies the state).

This confirms the contract has two primary functions:

  • set(uint256 _data): Stores a value.
  • get(): Retrieves the stored value.

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Contract Source Code

The source code of the contract is displayed as it was written:

solidity
Copy code
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract SimpleStorage {
    uint256 private data;

    function set(uint256 _data) public {
        data = _data;
    }

    function get() public view returns (uint256) {
        return data;
    }
}
  • Logic:
    • set: Allows the user to save a uint256 value in the contract’s state.
    • get: Returns the saved value without modifying the state.

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Contract Bytecode

  • The bytecode is the compiled version of the Solidity source code.
  • It is what gets deployed to the Ethereum blockchain.
  • This bytecode matches the source code provided in the screenshot.

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Summary

By completing the process, your contract will be displayed with all relevant details, as seen in the successful verification example above. This ensures a professional and polished deployment on the blockchain.