Add a network

In some cases, such as when interacting with smart contracts, your dapp must connect a user to a new network in MetaMask. Instead of the user adding a new network manually, which requires them to configure RPC URLs and chain IDs, your dapp can use the wallet_addEthereumChain and wallet_switchEthereumChain RPC methods to prompt the user to add a specific, pre-configured network to their MetaMask wallet.

These methods are specified by EIP-3085 and EIP-3326, and we recommend using them together.

1. wallet_addEthereumChain creates a confirmation asking the user to add the specified network to MetaMask.
2. wallet_switchEthereumChain creates a confirmation asking the user to switch to the specified network.

The confirmations look like the following:

Development and non-EVM networks

• To add a local development network such as Hardhat to MetaMask, see Run a development network.
• To add a non-EVM network such as Starknet to MetaMask, see Use non-EVM networks.

Example

The following is an example of using wallet_addEthereumChain and wallet_switchEthereumChain to prompt a user to add and switch to a new network:

try {
  await provider // Or window.ethereum if you don't support EIP-6963.
    .request({
      method: "wallet_switchEthereumChain",
      params: [{ chainId: "0xf00" }],
    })
} catch (switchError) {
  // This error code indicates that the chain has not been added to MetaMask.
  if (switchError.code === 4902) {
    try {
      await provider // Or window.ethereum if you don't support EIP-6963.
        .request({
          method: "wallet_addEthereumChain",
          params: [
            {
              chainId: "0xf00",
              chainName: "...",
              rpcUrls: ["https://..."] /* ... */,
            },
          ],
        })
    } catch (addError) {
      // Handle "add" error.
    }
  }
  // Handle other "switch" errors.
}