How to Add Custom RPC Networks to MetaMask

MetaMask is the most widely used Ethereum wallet, with over 30 million monthly active users. While it ships with Ethereum mainnet and a few popular networks pre-configured, you can add any EVM-compatible chain by providing a custom RPC endpoint.

This guide walks through adding custom RPC networks to MetaMask, choosing quality endpoints, and troubleshooting common issues.

What You'll Need

Before adding a network, gather these details:

RPC endpoint URL — an HTTPS address that accepts JSON-RPC calls (e.g., https://mainnet.base.org)

Chain ID — the network's unique numeric identifier (Base mainnet is 8453)

Currency symbol — the native gas token ticker (ETH, MATIC, BNB, etc.)

Block explorer URL (optional) — for viewing transaction details

You can find all of this for any supported chain on RPC Directory.

Adding a Network to MetaMask

Browser Extension

Click the MetaMask icon and open the network selector dropdown at the top left.

Scroll to the bottom and click Add network.

Select Add a network manually.

Fill in the fields:

Network name: A label you'll recognize (e.g., "Base Mainnet")

New RPC URL: Paste your endpoint

Chain ID: Enter the numeric ID

Currency symbol: The native token ticker

Block explorer URL: Optional but useful

Click Save. MetaMask switches to the new network automatically.

Mobile App

The flow is nearly identical: tap the hamburger menu → Settings → Networks → Add Network → Custom Networks, then fill in the same fields.

Choosing the Right RPC Endpoint

Not all endpoints perform equally under load. Here's what to consider:

Public endpoints are free and require no signup. They work for development, low-traffic dApps, and personal wallets. Limitations: rate limits (often 10–50 req/s), no uptime SLAs, and restricted method support (rarely archive data or debug_* calls).

Paid provider endpoints trade monthly cost for reliability. Expect 99.9%+ uptime SLAs, higher throughput (500–5,000 req/s), WebSocket support, and access to archive nodes and trace methods. If you're running anything production-grade, you'll want a paid tier eventually.

Check our public vs paid RPC guide for a deeper breakdown of when to upgrade.

Common Chain IDs

| Network | Chain ID | Symbol |

|---------|----------|--------|

| Ethereum | 1 | ETH |

| Base | 8453 | ETH |

| Arbitrum One | 42161 | ETH |

| Optimism | 10 | ETH |

| Polygon PoS | 137 | POL |

| BNB Chain | 56 | BNB |

| Avalanche C-Chain | 43114 | AVAX |

Find the full list—plus working endpoints—on the chains page.

Troubleshooting

"Could not fetch chain ID" or connection errors

The RPC URL is unreachable or returning unexpected responses. Check for typos, confirm the endpoint is live, or try a different endpoint from our directory.

"Invalid Chain ID" or network mismatch

The chain ID you entered doesn't match what the RPC node reports. Double-check the correct ID on RPC Directory and re-enter it.

"Network already exists"

The wallet won't add duplicate networks. Find the existing entry in your network settings and either edit it or delete it before adding a new one.

Transactions stuck or failing

This usually points to endpoint issues (rate limits, downtime) or network congestion. Try switching to a different RPC endpoint, or check a block explorer to see if the network itself is slow. Also confirm you have enough native tokens for gas.

Next Steps

With your network configured, you can bridge assets using cross-chain bridges, interact with dApps directly, or add more networks for multi-chain workflows.

Browse RPC Directory to find endpoints for any chain and compare providers when you're ready to move beyond public infrastructure.

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