How to Add a Network to MetaMask: Chain IDs & RPC URLs for 45 EVM Networks

Check MetaMask’s built-in list first

You often don’t need to type anything. MetaMask’s Help Center lists these as supported networks: Ethereum, Linea, Base, Polygon, BNB Chain, Arbitrum, Monad, Robinhood Chain, OP, Sei, Avalanche, zkSync Era, MegaETH, HyperEVM, Arc, Tempo (plus non-EVM Bitcoin, Solana and Tron). Some are on by default; the rest sit under “Additional networks” in the network menu with an Add or + button. Adding from that list uses MetaMask’s own default RPC, which also keeps Smart Transactions working on Ethereum, Linea, Base, Arbitrum and BNB Smart Chain.

How to add a custom network to MetaMask, step by step

1. 1

   Check whether MetaMask already offers the network

   MetaMask has a list of supported networks (Ethereum, Linea, Base, Polygon, BNB Chain, Arbitrum, OP, Avalanche, zkSync Era, Monad, Sei, HyperEVM, MegaETH and others). In the Extension, click the menu in the top right, select Networks and scroll to “Additional networks”, then click Add. On Mobile, tap the networks dropdown at the top of the Tokens tab, scroll to “Additional networks” and tap +. No typing needed.

2. 2

   Get the network details from a source you trust

   You need five values: network name, RPC URL, chain ID, currency symbol and (optionally) a block explorer URL. Use the network’s own documentation, chainid.network (Chainlist), or the verified table on this page. Never copy network details from a DM, an ad or a “support” agent.

3. 3

   Open “Add a custom network”

   Extension: menu in the top right → Networks → “Add a custom network”. Mobile: networks dropdown at the top of the Tokens tab → Custom tab → “Add a custom network”.

4. 4

   Enter the five fields and save

   Type the network name, paste the RPC URL, enter the chain ID (for example 8453 for Base) and the currency symbol (ETH, POL, BNB, AVAX…), add the explorer URL and click Save. MetaMask runs basic checks and warns you if something looks wrong, such as an RPC that reports a different chain ID.

5. 5

   Switch to the network and check your address

   Select the new network. Your 0x address is the same on every EVM network, so any funds already sent there appear at the same address. If a token doesn’t show, import it with its contract address on that network.

6. 6

   Get a little of the network’s gas coin

   Every transaction is paid in the network’s own coin: ETH on Arbitrum, Base, OP, Linea, Scroll, ZKsync and most other L2s; POL on Polygon; BNB on BNB Chain; AVAX on Avalanche; xDAI on Gnosis. Without it you can see your tokens but can’t move them.

Using a Ledger? Connect it to MetaMask and add the network the same way; Ledger’s own guide covers it. Funds already sent to the wrong network? Follow how to find and recover crypto sent to the wrong network — adding the network is usually step one. Tokens still missing after you switch? Import them with the verified USDC, USDT and WETH contract addresses.

Is adding a network safe? What a bad RPC can do

Adding a network does not give anyone access to your funds; only your signature does. But MetaMask says it does not verify custom networks, and that a malicious network provider can lie about the state of the blockchain, withhold your transactions and record your network activity and IP address. When a website asks to add a network, the pop-up shows the network name, RPC URL, chain ID, currency symbol and explorer the site supplied; trust them only as much as you trust the site.

For developers: add or switch networks from your dapp

Call wallet_switchEthereumChain (EIP-3326) first. If the wallet returns error 4902, the chain isn’t added yet, so call wallet_addEthereumChain (EIP-3085) with the chain ID in hex, name, native currency, RPC URLs and explorer. This is exactly what the Add to wallet buttons above do.

// Switch to Base, or add it if the wallet doesn't have it yet (EIP-3326 + EIP-3085)
async function useBase() {
  const base = {
    chainId: '0x2105', // 8453
    chainName: 'Base',
    nativeCurrency: { name: 'Ether', symbol: 'ETH', decimals: 18 },
    rpcUrls: ['https://mainnet.base.org'],
    blockExplorerUrls: ['https://basescan.org'],
  }
  try {
    await window.ethereum.request({
      method: 'wallet_switchEthereumChain',
      params: [{ chainId: base.chainId }],
    })
  } catch (err) {
    if (err.code === 4902) {
      await window.ethereum.request({ method: 'wallet_addEthereumChain', params: [base] })
    } else throw err // 4001 = user rejected, -32002 = request already pending
  }
}

The full list, with both RPCs per network, is in the JSON download below. Public RPCs are free but rate-limited; for production traffic use your own node or a provider key, and keep a fallback.

How we verified the list

Candidate details came from the community registry behind Chainlist (ethereum-lists/chains) and each network’s docs. On October 21, 2026 we called eth_chainId and eth_getBlockByNumber on every RPC listed: each returned the listed chain ID and a block less than 15 seconds old, and each sends the CORS header browsers need. RPCs that failed (for example rpc.sepolia.org) and networks whose latest block was stale at check time (Arbitrum Nova, ~14 minutes) were left out. Explorers were checked for a working page.