verify-contract

How to verify smart contracts using Etherscan V2 API

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Overview

This repository provides a sample project using Hardhat + Etherscan V2 API to deploy and verify smart contracts on Etherscan. It includes scripts and configuration needed to automatically submit your contract's source code, compiler settings, etc., for verification.

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Features

• Sample Solidity contracts under contracts/
• Deployment scripts
• Verification script using Etherscan V2 API
• Configuration for networks / Etherscan API key
• Contract address tracking (contract-addresses.txt)

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Prerequisites

• Node.js (v18+ recommended)
• npm or yarn or pnpm
• Hardhat
• An Etherscan API key
• Network(s) configured in Hardhat to target (e.g. Ethereum mainnet, testnets, or others)

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Setup

1. Clone the repository:

   git clone https://github.com/holyaustin/verify-contract.git
   cd verify-contract

Install dependencies:

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npm install
# or
yarn
Create .env file from .env copy and fill in the required variables:
```textCopy codeETHERSCAN_API_KEY=your_etherscan_api_key# other network keys or RPC endpoints if neededConfigure hardhat.config.js to include the networks you plan to deploy & verify to.# UsageDeploy```sh
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npx hardhat run scripts/deploy.js --network <your_network>
This will deploy your contract and record the address into contract-addresses.txt.
Verify
```shCopy codenpx hardhat run scripts/verify.js --network <your_network> --contract <ContractName> --address <contract_address>Alternatively, you can configure your verification script to read from the contract-addresses.txt and automatically pick up the addresses.### Etherscan V2 APIEtherscan V2 APIThis project uses Etherscan V2 API for verification, which allows submitting:contract source codecompiler versionoptimizer settingslicense typeconstructor arguments (if any)Make sure your Hardhat build output matches exactly what you submit for verification (contract name, solidity version, etc.)TroubleshootingAPI rate limits: The Etherscan API has limits. If you get rate-limited, you may need to wait or upgrade your plan.Mismatched compiler settings: If verification fails, double-check that the compiler version/optimizer settings in your Hardhat config are exactly what you used in the contract.Flattened contracts or imports: If you have multiple files or imports, ensure the source file structure matches what Etherscan expects (or use a standard flattening process).Constructor args: If your contract constructor takes arguments, you’ll need to pass them (in ABI/encoded form) during verification.ContributingFeel free to open issues or pull requests. Some ideas:Add examples for different networks (Polygon, BSC, etc.)Support more Etherscan-like block explorersBetter error handling / retries