hardhat-zksync-verify

This plugin is used to verify contracts on the ZKsync Era network.

Changelog

Prerequisite

To use hardhat-zksync-verify in your project, ensure the following:

• Node.js version 18 or higher is installed.
• Hardhat version 2.16.0 or higher is installed as a dependency.

Setup

The @matterlabs/hardhat-zksync-verify plugin is used in conjunction with @nomicfoundation/hardhat-verify and it supports backward compatibility. To use it, install both plugins and then import @matterlabs/hardhat-zksync-verify in the hardhat.config.ts file.

yarn add -D @matterlabs/hardhat-zksync-verify @nomicfoundation/hardhat-verify

Configuration

Import the plugin in the hardhat.config.ts file:

import "@matterlabs/hardhat-zksync-verify";

networks: {
    sepolia: {
      url: "https://sepolia.infura.io/v3/<API_KEY>" // The Ethereum Web3 RPC URL (optional).
    },
    zkTestnet: {
      url: "https://sepolia.era.zksync.dev", // The testnet RPC URL of ZKsync Era network.
      ethNetwork: "sepolia", // The Ethereum Web3 RPC URL, or the identifier of the network (e.g. `mainnet` or `sepolia`)
      zksync: true,
    }
},

Updates introduced in plugin version 1.7.0

Etherscan verification is supported. To enable it, configure the etherscan property in the Hardhat configuration:

etherscan: {
  apiKey: 'APIKEY'
}

If the etherscan property is configured and enabled, verification will run on Etherscan. Otherwise, the plugin will default to verifying on the ZKsync block explorer. For more information on how to create api keys, please visit the documentation. For more information on how to configure etherscan for multiple api keys, please visit the documentation The plugin provides pre-configured chain settings zksyncsepolia and zksyncmainnet, so users don't need to create custom chains.

etherscan: {
  apiKey: {
    ......
    zksyncsepolia: 'APIKEY',
    zksyncmainnet: 'APIKEY'
  }
}

Additional network properties:

• zkTestnet is an arbitrary ZKsync Era network name. You can select this as the default network using the defaultNetwork property.
• url is a field with the URL of the ZKsync Era node in case of the ZKsync Era network (with zksync flag set to true), or the URL of the Ethereum node. This field is required for all ZKsync Era and Ethereum networks used by this plugin.
• ethNetwork is a field with the URL of the Ethereum node. You can also provide network name (e.g. sepolia) as the value of this field. In this case, the plugin will either use the URL of the appropriate Ethereum network configuration (from the networks section), or the default ethers provider for the network if the configuration is not provided. This field is required for all ZKsync networks used by this plugin.
• zksync is a flag that indicates a ZKsync Era network configuration. This field is set to true for all ZKsync Era networks. If you want to run a hardhat-verify verification, this field needs to be set to false. If set to true, the verification process will try to run the verification process on the ZKsync Era network.
• verifyURL is a field that specifies the verification endpoint for the connected ZKsync network. From version 1.7.0, the plugin automatically resolves this endpoint based on the network configuration. If you are using a custom chain with an API compatible with the zksync block explorer, you can manually set the URL here.
• browserVerifyURL - Introduced in version 1.7.0 of the plugin, this field automatically resolves the browser URL based on the network configuration. If you're using a custom chain, you can manually specify the URL here.
• enableVerifyURL - Introduced in version 1.7.0 of the plugin, this flag forces verification on the ZKsync block explorer. It allows you to verify the same contract on both Etherscan and the ZKsync block explorer.

Commands

yarn hardhat verify --network <network> <contract address>

This command verifies the contract on the given network with the given contract's address.

When executed in this manner, the verification task attempts to compare the compiled bytecode of all the contracts in your local environment with the deployed bytecode of the contract you are seeking to verify. If there is no match, it reports an error.

yarn hardhat verify --network <network> <contract address> --contract <fully qualified name>

With the --contract parameter you can also specify which contract from your local setup you want to verify by specifying its Fully qualified name. Fully qualified name structure looks like this: "contracts/AContract.sol:TheContract"

Constructor arguments

If your contract was deployed with the specific constructor arguments, you need to specify them when running the verify task. For example:

yarn hardhat verify --network testnet 0x7cf08341524AAF292255F3ecD435f8EE1a910AbF "Hi there!"

If your constructor takes a complex argument list, you can write a separate javascript module to export it. For example, create an arguments.js file with the following structure:

module.exports = [
  "a string argument",
  "0xabcdef",
  "42",
  {
    property1: "one",
    property2: 2,
  },
];

Include it in the verify function call by adding a new parameter: --constructor-args arguments.js:

yarn hardhat verify --network testnet 0x7cf08341524AAF292288F3ecD435f8EE1a910AbF --constructor-args arguments.js

The hardhat-zksync-verify plugin also supports the verification with encoded constructor parameters.

In order to use the encoded parameters, you need to specify a separate javascript module and export them as a non-array parameter. It is important for encoded arguments to start with 0x in order to be recognized by the plugin. For example:

module.exports = "0x0x00087a676164696a61310000087a676164696a61310000000000000000000000008537b364a83f5c9a7ead381d3baf9cbb83769bf5";

Verification status check

The verification process consists of two steps:

• A verification request is sent to confirm if the given parameters for your contract are correct.
• Then, we check the verification status of that request. Both steps run when you run the verify task, but you will be able to see your specific verification request ID.

Verify smart contract programmatically

If you need to run the verification task directly from your code, you can use the hardhat verify:verify task with the previously mentioned parameters with the difference in using --address parameter when specifying contract's address.

const verificationId = await hre.run("verify:verify", {
  address: contractAddress,
  contract: contractFullyQualifedName,
  constructorArguments: [...]
});

This task returns a verification id if the request was successfully sent.

You can use this id to check the status of your verification request as described in the section above.

If you are using encoded constructor args, constructorArguments parameter should be a non-array value starting with 0x.

const verificationId = await hre.run("verify:verify", {
  address: contractAddress,
  contract: contractFullyQualifedName,
  constructorArguments: "0x12345...",
});