hashscan-verify

A Hardhat plugin for verifying smart contracts on HashScan (Hedera's Sourcify-based contract verification service).

• Works for Hedera Mainnet (295), Testnet (296), Previewnet (297) and Local (298)
• No API key needed
• Direct integration with HashScan's Sourcify API
• Automatic contract verification status checking
• Clean error messages

Install

npm i -D hashscan-verify

Usage

In your hardhat.config.ts:

import { defineConfig } from "hardhat/config";
import hashscanVerify from "hashscan-verify";

export default defineConfig({
  plugins: [hashscanVerify],
  networks: {
    mainnet:     { url: "https://mainnet.hashio.io/api" },
    testnet:     { url: "https://testnet.hashio.io/api" },
    previewnet:  { url: "https://previewnet.hashio.io/api" },
    local:       { url: "http://localhost:7546" },
  },
});

Note: The plugin automatically sets the correct chain IDs for Hedera networks.

Verify a contract

npx hardhat hashscan-verify 0xYourContractAddress --contract contracts/MyContract.sol:MyContract --network testnet

Features

Automatic Verification Status Check

The plugin checks if your contract is already verified before attempting verification:

$ npx hardhat hashscan-verify 0x... --contract contracts/Counter.sol:Counter --network testnet
Contract is already verified with perfect match.

View on HashScan: https://hashscan.io/testnet/contract/0x...

Clean Error Messages

Meaningful error handling with helpful suggestions:

• Invalid contract address format
• Contract not found in artifacts
• Missing build info (suggests recompilation)
• Network connection issues

Network Support

Supports both legacy hedera_* and simplified network names:

• mainnet or hedera_mainnet (Chain ID: 295)
• testnet or hedera_testnet (Chain ID: 296)
• previewnet or hedera_previewnet (Chain ID: 297)
• local or hedera_local (Chain ID: 298)

Environment Variables

• HASHSCAN_API_URL or SOURCIFY_API_URL - Override the API endpoint (defaults to HashScan's Sourcify)

Examples

Basic Verification

npx hardhat hashscan-verify 0x7A0505Eb4af57Eefb9B69619DB3bfc26348DE73A --contract contracts/Counter.sol:Counter --network testnet

With Constructor Arguments

npx hardhat hashscan-verify 0x... --contract contracts/Token.sol:MyToken "My Token" "MTK" 1000000 --network mainnet

Notes

• On Hedera Testnet/Previewnet, verifications are wiped on periodic resets—just re-run verify after redeploy
• Foundry users: no wrapper needed. Use forge directly with HashScan's Sourcify:

  forge verify-contract --chain-id 296 \
    --verifier sourcify \
    --verifier-url https://server-verify.hashscan.io \
    <ADDRESS> src/MyContract.sol:ContractName

Development

Build the plugin:

npm run build

Publish (after build):

npm publish

License

MIT