How to bridge tokens to Arbitrum? (L2 tutorial)

Network Configuration

1. Visit bridge.arbitrum.io and click the “Add/switch to Arbitrum network” button located in the center of the page to trigger automatic network setup in MetaMask.

2. Alternatively, manually configure Arbitrum One by opening MetaMask, selecting “Ethereum Mainnet”, then choosing “Custom RPC” at the bottom of the network list.

3. Input the following parameters: Network Name: Arb1, RPC URL: https://arb1.arbitrum.io/rpc, Chain ID: 42161, Currency Symbol: ETH, Block Explorer URL: https://arbiscan.io.

4. Developers may opt for Alchemy or Infura as RPC providers instead of the default endpoint.

5. Confirm the configuration and save the network—MetaMask will now display “Arbitrum One” as an available option.

Depositing Assets from Ethereum Mainnet

1. Ensure your MetaMask wallet is connected to Ethereum Mainnet before initiating any deposit.

2. Select the desired token from the dropdown menu on the bridge interface—only ERC-20 compatible tokens are supported.

3. Enter the amount in the L1 field, then click “Deposit” and approve the transaction in MetaMask.

4. The transaction requires confirmation on Ethereum L1; gas fees must be paid in ETH held on the mainnet.

5. After confirmation, assets typically appear on Arbitrum One within 10 minutes to one hour depending on network congestion.

Accessing Arbitrum-Based dApps

1. Switch MetaMask to the Arbitrum One network to view bridged balances and interact with deployed contracts.

2. Navigate to portal.arbitrum.one for a curated directory of decentralized applications including DeFi protocols, NFT marketplaces, and wallet integrations.

3. All standard Ethereum tooling—including Hardhat, Truffle, ethers.js, and The Graph—functions natively without modification.

4. Smart contracts written in Solidity, Vyper, or Yul deploy directly to Arbitrum without code changes due to full EVM equivalence.

5. No custom client software is required for end users; interaction remains identical to Ethereum L1 in terms of UX flow and signature handling.

Withdrawing Funds Back to Ethereum

1. Initiate withdrawal only after switching MetaMask to the Arbitrum One network.

2. Choose the token to withdraw using the dropdown selector and specify the amount in the L2 field.

3. Click “Withdraw”, confirm the transaction in MetaMask, and wait for the on-chain confirmation.

4. A mandatory seven-day challenge period begins immediately after submission—this is enforced by Optimistic Rollup’s fraud-proof mechanism.

5. Once the challenge window expires, users must manually click “Claim” on the bridge interface to finalize settlement on Ethereum Mainnet.

Frequently Asked Questions

Q1: Can I bridge non-ERC-20 tokens like BTC or SOL to Arbitrum?Only ERC-20 tokens native to Ethereum Mainnet are eligible for bridging. Wrapped representations (e.g., WBTC, wSOL) may be used if already deployed on Ethereum and verified on Arbitrum’s token list.

Q2: Why does my bridged ETH not show up in Uniswap on Arbitrum?This occurs when MetaMask remains on Ethereum Mainnet instead of Arbitrum One. Double-check the active network and refresh the dApp page after switching.

Q3: Is it possible to use the Arbitrum bridge without MetaMask?The official bridge supports WalletConnect-compatible wallets. Users can connect via Trust Wallet, Coinbase Wallet, or Rainbow as long as they support EIP-1193 and EIP-1559 transactions.

Q4: What happens if I send ETH to Arbitrum but forget to include gas for subsequent transactions?Arbitrum requires ETH for L2 gas fees. Without sufficient ETH balance on Arbitrum One, no contract interactions—including swaps or approvals—will execute successfully.