This guide explains how to add custom RPC MetaMask entries and how to connect MetaMask to different blockchains (EVM-compatible networks). It covers both the browser extension and mobile app with practical steps, real-world tips from daily use, and links to chain-specific pages like add-polygon, add-avalanche, and add-fantom.
I use MetaMask daily across a desktop browser and my phone for swaps, staking, and dApp interactions. That hands-on time shaped the advice below. And I’ve learned the hard way: one wrong Chain ID and a transaction will fail (or worse, look like it went through).
There are good reasons to add a custom RPC to MetaMask:
But custom RPCs carry trade-offs (explained later). For many DeFi tasks, the built‑in options work fine. For development, multi-chain activity, or when public endpoints are rate‑limited, custom RPCs are useful.
When you add a network you’ll be asked for a handful of items. All must match the target blockchain’s values.
| Field | What it is | Example (Polygon mainnet) |
|---|---|---|
| Network Name | Friendly label shown in MetaMask | Polygon Mainnet |
| New RPC URL | JSON‑RPC endpoint MetaMask will query | https://polygon-rpc.com/ |
| Chain ID | Numeric identifier for the chain (use decimal) | 137 |
| Currency Symbol | Native token label (optional but helpful) | MATIC |
| Block Explorer URL | Optional link for txs and addresses | https://polygonscan.com/ |
(Image: MetaMask network settings screen — placeholder)
Note: MetaMask expects the Chain ID number (decimal). If a mismatch happens you may see signature or network errors.
Practical tip: copy/paste fields from an official chain page (or the chain’s docs) to avoid typos. I keep a short list of verified RPC URLs in a private note for this reason.
On mobile you can also use WalletConnect for some dApps but adding the network directly makes it smoother when a dApp requires that chain.
(Image: MetaMask mobile Add Network screen — placeholder)
Below are concise examples for common EVM-compatible chains. Verify RPC endpoints against each chain’s official documentation before using.
How to connect MetaMask to Polygon network
How to connect MetaMask to Avalanche network
How to connect MetaMask to Fantom
These examples show how to add custom RPC MetaMask entries for specific chains. I regularly switch between these on the desktop extension for swaps and staking UI tests.
I once had a token transfer stuck because my custom RPC was returning an old nonce; switching to a different RPC fixed it within minutes. Small changes like that matter.
A custom RPC is only as trustworthy as the node you point to. RPC endpoints can observe queries (addresses, tx history) and can give misleading responses if malicious. They cannot extract your private keys from MetaMask (MetaMask is non-custodial and signs locally), but they can:
Best practices:
Who this is for:
Who should look elsewhere or be cautious:
If you plan to transact frequently across chains, consider combining MetaMask with a hardware wallet (see connect-ledger and connect-trezor).
Adding a custom RPC in MetaMask is straightforward and unlocks many EVM-compatible chains. Follow the steps above, double-check chain parameters, and prefer known RPC endpoints (or run your own) for sensitive activities. What I’ve found is that small verification steps—confirming the Chain ID and explorer URL—save time and headaches.
If you’re installing MetaMask for the first time, see the setup guides: install-metamask-extension and install-metamask-mobile-app. For recovery and backup best practices, read backup-recovery-seed. Want chain‑specific instructions? Visit add-polygon, add-avalanche, or add-fantom.
Ready to add a network? Try a small test transaction first (low value) to confirm RPC behavior before moving larger amounts. And remember: a software wallet is convenient, but balance convenience with proper security steps for serious funds.