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Version: 3.0.0

Switching or Adding EVM Chains

This page explains how to configure your dapp so that it connects to supported networks, which include all EVM-compatible L1/L2 networks.

Switching or adding alternative EVM-compatible chains​

Coinbase Wallet SDK and Coinbase Wallet clients support both EIP-3326 wallet_switchEthereumChain and EIP-3085 wallet_addEthereumChain requests for switching networks.

For dapps supporting multiple networks, Coinbase Wallet SDK only needs 1 rpcUrl -- the rpcUrl of the chain the dapp wishes to default users to.

If Wallet SDK receives either a wallet_switchEthereumChain or wallet_addEthereumChain request for a whitelisted network then it switches the user to that network after asking approval from the user.

Coinbase Wallet clients handle wallet_addEthereumChain requests for non-whitelisted networks (for example, a network such as Harmony One which is not currently supported by clients by default).

A dapp can determine if a network is whitelisted or not by sending a wallet_switchEthereumChain request for that network. If error code 4092 is returned, then the network is not supported by default by the client wallet.

Example​

Here's how to request the wallet switch networks:

ethereum.request({
  method: 'wallet_switchEthereumChain',
  params: [{ chainId: '0xA86A' }]
}).then(response => console.log(response))

Here's how to request the client wallet add a new network

ethereum.request({
  method: 'wallet_addEthereumChain',
  params: [{
    chainId: '0x63564C40',
    rpcUrls: ['https://api.harmony.one'],
    chainName: 'Harmony Mainnet',
    nativeCurrency: { name: 'ONE', decimals: 18, symbol: 'ONE' },
    blockExplorerUrls: ['https://explorer.harmony.one'],
    iconUrls: ['https://harmonynews.one/wp-content/uploads/2019/11/slfdjs.png'],
  }],
}).then(response => console.log(response))

Many dapps attempt to switch to a network with wallet_switchEthereumChain, determine if the network is supported by the wallet based on the error code, and follow with a wallet_addEthereumChain request if the network is not supported. Here's an example:

try {
  // attempt to switch to Harmony One network
  const result = await ethereum.send('wallet_switchEthereumChain', [{ chainId: `0x63564C40` }])
} catch (switchError) {
  // 4902 indicates that the client does not recognize the Harmony One network
  if (switchError.code === 4902) {
      await ethereum.request({
        method: 'wallet_addEthereumChain',
        params: [{
          chainId: '0x63564C40',
          rpcUrls: ['https://api.harmony.one'],
          chainName: 'Harmony Mainnet',
          nativeCurrency: { name: 'ONE', decimals: 18, symbol: 'ONE' },
          blockExplorerUrls: ['https://explorer.harmony.one'],
          iconUrls: ['https://harmonynews.one/wp-content/uploads/2019/11/slfdjs.png'],
        }],
      })
  }
}

Next steps:

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