How to add Arc to MetaMask

By the arky team · Updated 4 October 2026 · Sources linked inline

Arc network details for MetaMask

These are the official values from Circle's Arc documentation. Copy them exactly: a wrong chain ID is the most common reason MetaMask refuses to save a network.

Source: Arc docs: Connect to Arc and Arc docs: add Arc to a wallet. We also queried both public RPCs with eth_chainId on 4 October 2026: mainnet answered 0x13b2 (5042) and testnet 0x4cef52 (5042002).

Step by step: add Arc mainnet

1. Open MetaMask's network list. Open MetaMask, click the network selector at the top left and choose Add a custom network (on some versions: Add network, then Add a network manually).
2. Enter the Arc network details. Type Arc as the network name, https://rpc.mainnet.arc.io as the RPC URL, 5042 as the chain ID, USDC as the currency symbol and https://explorer.arc.io as the block explorer URL.
3. Save and switch to Arc. Click Save. MetaMask checks the chain ID against the RPC; if it matches, Arc appears in your network list. Select it.
4. Fund the wallet with USDC. Your balance shows 0 USDC until you bring USDC onto Arc, for example with Circle CCTP or an exchange withdrawal to the Arc network.
5. Connect to an Arc app. Open an Arc app such as arky at app.arky.bet, connect MetaMask and approve the network if asked. You pay gas in USDC.

The same steps work in Rabby, Coinbase Wallet, OKX Wallet and any EVM wallet that lets you add a custom network. Many apps also prompt your wallet to add or switch to Arc automatically when you connect.

Add Arc Testnet instead

Developers and testers should use Arc Testnet: name Arc Testnet, RPC https://rpc.testnet.arc.io, chain ID 5042002, symbol USDC, explorer https://explorer.testnet.arc.io. Test USDC is free from Circle's faucet; see the Arc testnet faucet guide. Testnet USDC has no value and cannot be bridged to mainnet.

Things that work differently on Arc

• Gas is USDC. MetaMask shows the native balance as USDC. You do not need ETH; an "insufficient funds for gas" warning means you need more USDC on Arc.
• 18 vs 6 decimals. Natively, USDC on Arc has 18 decimals so it can pay gas. The USDC token contract (0x3600000000000000000000000000000000000000) uses the standard 6 decimals. If you import that token manually, you are looking at the same dollars, not a second balance (Arc docs: add Arc to a wallet).
• Minimum gas price. Arc rejects transactions with a maxFeePerGas below 20 gwei. MetaMask's defaults are normally fine; if you set custom gas, keep it above that floor.
• Fast finality. A confirmed Arc transaction is final in under a second. There is no need to wait for extra confirmations (Arc docs: system overview).

Check you are on the real Arc

Copycat networks and fake "Arc" RPCs are a common way to phish wallets. Only use RPC URLs ending in arc.io or a provider listed in the Arc docs (Alchemy, Blockdaemon, dRPC, QuickNode), and confirm the chain ID is 5042. On chainlist-style sites, compare every field with the table above before you click "Add". A real Arc network never asks you to sign a message or approve a token just to be added.

Troubleshooting

Next: get USDC onto Arc and start trading

With Arc in MetaMask, fund the wallet: our bridge USDC to Arc guide covers Circle CCTP, exchanges and bridges. Then open app.arky.bet. arky is the trading terminal of Arc: the trading terminal, memecoin launchpad and USDC prediction markets, with Scout, your AI agent, proposing trades your wallet signs. For the bigger picture, read what is Arc or browse the Arc ecosystem.