Add CCIP Networks for Cross-Chain Token Tutorials (Hardhat)

Guide Versions

This guide is available in multiple versions. Choose the one that matches your needs.

The smart-contract-examples repository includes default configurations for common CCIP testnet networks. This guide shows how to add support for additional networks.

Add a Network

Add the network configuration to config/networks.ts:

export const configData = {
  // ... existing networks
  optimismSepolia: {
    chainFamily: "evm",
    chainId: 11155420,
    chainSelector: "5224473277236331295",
    router: "0x114A20A10b43D4115e5aeef7345a1A71d2a60C57",
    rmnProxy: "0xb40A3109075965cc09E93719e33E748abf680dAe",
    tokenAdminRegistry: "0x1d702b1FA12F347f0921C722f9D9166F00DEB67A",
    registryModuleOwnerCustom: "0x49c4ba01dc6F5090f9df43Ab8F79449Db91A0CBB",
    link: "0xE4aB69C077896252FAFBD49EFD26B5D171A32410",
    confirmations: 2,
    nativeCurrencySymbol: "ETH",
  },
}

Set the RPC URL:

npx env-enc set OPTIMISM_SEPOLIA_RPC_URL

The network is now available in all Hardhat tasks using --network optimismSepolia.

Environment variable naming: The system converts network names from camelCase to SNAKE_CASE and adds _RPC_URL. Examples: optimismSepolia → OPTIMISM_SEPOLIA_RPC_URL, avalancheFuji → AVALANCHE_FUJI_RPC_URL.

Configuration Fields

Field	Required	Description	Source
`chainFamily`	Yes	Blockchain VM type: `"evm"` for Ethereum-compatible chains, `"svm"` for Solana	`config/types.ts`
`chainId`	Yes	EVM chain ID	Blockchain's official documentation (preferred) or ChainList
`chainSelector`	Yes	CCIP identifier for the network	CCIP Directory
`router`	Yes	CCIP Router contract address	CCIP Directory
`rmnProxy`	Yes	RMN Proxy contract address	CCIP Directory
`tokenAdminRegistry`	Yes	Token Admin Registry address	CCIP Directory
`registryModuleOwnerCustom`	Yes	Registry Module Owner address	CCIP Directory
`link`	Yes	LINK token contract address	CCIP Directory
`confirmations`	No	Number of block confirmations before considering transaction final	Blockchain's finality characteristics and your risk tolerance
`nativeCurrencySymbol`	No	Native gas token symbol (e.g., `"ETH"`, `"AVAX"`, `"POL"`)	Blockchain's official documentation

Find all CCIP addresses in the CCIP Directory - Testnet or CCIP Directory - Mainnet.

Test

Deploy a token to verify the configuration:

npx hardhat deployToken --name "Test Token" --symbol TEST --network optimismSepolia

Contract Verification (Optional)

Most networks are natively supported. Add --verifycontract when deploying:

npx hardhat deployToken --name "Test Token" --symbol TEST --network optimismSepolia --verifycontract

For networks not in Hardhat's chain descriptors, add to hardhat.config.ts:

chainDescriptors: {
  12345: {
    name: "New Network",
    chainType: "generic",
    blockExplorers: {
      etherscan: {
        name: "NewScan",
        url: "https://newscan.io",
        apiUrl: "https://api.newscan.io/api",
      },
    },
  },
}

With Etherscan API V2, a single ETHERSCAN_API_KEY works across all Etherscan-compatible networks.