How Do You Add a Custom RPC Endpoint in MetaMask?

13 October 2026

Adding a custom RPC endpoint in MetaMask lets you connect the wallet to Ethereum networks that are not listed by default - such as testnets like Sepolia, layer‑2 chains like Arbitrum, or private networks. The process takes about two minutes once you have the network details.

What you need before you start

You need the network’s RPC URL, chain ID, currency symbol, and (optionally) a block explorer URL. These are usually published on the network’s official documentation or developer portal. Do not copy details from random forum posts; incorrect chain IDs are a common cause of the “signature invalid” error covered elsewhere on this site.

Step‑by‑Step Instructions

1. Open MetaMask and Access Settings

Click the MetaMask extension icon in your browser. If you are not already on the main wallet view, click the three‑dot menu in the top‑right corner. From the dropdown, select Settings.

2. Navigate to Networks

In the Settings menu, find and click Networks. This page shows the networks MetaMask already has configured - Ethereum Mainnet, several testnets, and any networks you have added before.

3. Click “Add Network”

On the Networks page, click the Add Network button. MetaMask will present a list of popular networks it can auto‑configure. To add a custom one, scroll to the bottom of that list and click Add a network manually.

4. Enter the Network Details

A form with the following fields appears. Fill in each one accurately:

• Network Name - A label for your own reference, e.g., “Arbitrum One” or “Sepolia Testnet”.
• New RPC URL - The RPC endpoint provided by the network. This is the server your wallet will query for balances and send transactions to. It should start with https:// (or wss:// for WebSocket connections). Do not use an RPC URL from a source you do not trust - malicious endpoints can return false data or intercept transaction details.
• Chain ID - A numeric identifier for the network. This must match exactly. An incorrect chain ID will cause transactions to fail with a “wrong chain ID” error. The chain ID is not the same as the network ID; use the one the network specifies.
• Currency Symbol - The ticker for the network’s native token, e.g., ETH for Ethereum mainnet or Sepolia, ARB for Arbitrum.
• Block Explorer URL (optional) - The URL of a block explorer so MetaMask can link to transaction details. This is not required for the connection to work, but it is useful.

5. Save the Network

Click Save. MetaMask will automatically switch to the new network. You will see the network name and its currency symbol displayed at the top of the wallet interface.

Verifying the Connection

Once you have added the network, check that it is working:

1. Look at the network name at the top of the MetaMask window. It should show the name you entered.
2. Your balance should display 0 (or whatever balance you hold on that network). If your ETH balance shows zero and you expected a balance, see the article on why balances can appear zero after a MetaMask update - it is often a display issue rather than a lost balance.
3. Try a simple read‑only operation, such as checking a token balance on a block explorer, before sending any transactions.

Common Mistakes and How to Avoid Them

• Wrong RPC URL - A typo in the URL, or using an HTTP endpoint when the network requires HTTPS, will prevent MetaMask from connecting. Double‑check the URL from the network’s official documentation.
• Incorrect chain ID - This is the most frequent error. MetaMask will not warn you if the chain ID is wrong; transactions will fail with a “signature invalid” or “nonce too high” error. Always verify the chain ID from the network’s official source.
• Adding a network you already have - MetaMask does not prevent duplicate network entries. If you see two entries for the same network, you can delete the duplicate from the Networks settings.
• Using a public RPC that is rate‑limited - Many free RPC endpoints limit requests. If your transactions are slow or fail intermittently, consider using a private RPC or a service like Infura or Alchemy, which provide dedicated endpoints.

Removing a custom network

To remove a network you no longer need, go to Settings > Networks, click the network name, and scroll to the bottom of the details page. Click Delete and confirm. This does not affect your wallet or funds - it just removes the entry from MetaMask.

Security Note

Only add custom RPC endpoints for networks you trust. A malicious RPC provider could serve fake balances, censor your transactions, or attempt to phish your private keys by prompting you to sign deceptive messages. If you are connecting to a testnet or a lesser‑known L2, cross‑reference the network details with its official website or documentation.

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