# Add custom chains

> Add custom chains in the MetaMask Developer Dashboard | Embedded Wallets

You can add any EVM-compatible chain to your project through the dashboard or by passing chain configuration directly to the SDK during initialization.

## Add a custom chain in the dashboard

1. Go to the [MetaMask Developer Dashboard](https://developer.metamask.io).
2. Select your project, then click the **Chains & Networks** tab.
3. Click **Add a Custom Network**.
4. Fill in the chain details: Logo URL, Network Name, Currency Symbol, Chain ID, Block Explorer URL, and RPC URL.
5. Click **Save Network**.

## Add chains in code (Web SDK)

You can also override or extend chain configuration in code using the `chains` parameter at SDK initialization. Only chains listed in the `chains` array will be available in the SDK.

```typescript title="App.tsx"

const evmChainConfig = {
  chainNamespace: CHAIN_NAMESPACES.EIP155,
  chainId: '0xaa36a7', // Sepolia in hex
  rpcTarget: 'https://1rpc.io/sepolia',
  displayName: 'Ethereum Sepolia Testnet',
  blockExplorerUrl: 'https://sepolia.etherscan.io',
  ticker: 'ETH',
  tickerName: 'Ethereum',
  decimals: 18,
  logo: 'https://cryptologos.cc/logos/ethereum-eth-logo.png',
}

const arbitrumChainConfig = {
  chainNamespace: CHAIN_NAMESPACES.EIP155,
  chainId: '0x66eee', // Arbitrum Sepolia (421614 in hex)
  rpcTarget: 'https://sepolia-rollup.arbitrum.io/rpc',
  displayName: 'Arbitrum Sepolia Testnet',
  blockExplorerUrl: 'https://sepolia.arbiscan.io/',
  ticker: 'AETH',
  tickerName: 'AETH',
  decimals: 18,
  logo: 'https://arbitrum.foundation/images/logo.png',
}

const web3auth = new Web3Auth({
  clientId: '<YOUR_CLIENT_ID>',
  web3AuthNetwork: WEB3AUTH_NETWORK.SAPPHIRE_MAINNET,
  chains: [evmChainConfig, arbitrumChainConfig],
  defaultChainId: '0x66eee', // which chain to use by default
})
```

:::note

SDK package names and code identifiers (`@web3auth/modal`, `Web3Auth`, `WEB3AUTH_NETWORK`) are unchanged from the original Web3Auth SDK.

:::