In this Arbitrum tutorial, we will explain how to use Arbitrum L2, connect Arbitrum to MetaMask and how to bridge ETH to Arbitrum.

Arbitrum Layer 2 Tutorial

What is Arbitrum & Layer 2?

Arbitrum is an Etheruem, layer 2 solution developed by Offchain Labs. The mainnet beta of Arbitrum One was only released to developers in May 2021 to enable a smooth onboarding and before anyone risks losing their money. By early August 2021, they had already onboarded over 400 DApps to the beta and on August 31st, they publicly launched Arbitrum One.

Similar to Optimism and Polygon, Arbitrum was designed to boost Ethereum’s transactional throughput and minimise transaction fees at the same time. It does this using something called “transaction rollups” to record batches of transactions on the Ethereum main chain. It then executes these on a cheap, scalable layer 2 sidechain which helps to offload most of the computational and storage burden from Ethereum.

Because of its very efficient roll-up technology, Arbitrum can cut your Etheruem fees down to just a fraction of what they would on the Ethereum Mainnet, while still providing sufficient incentives for validators.

Arbitrum Supported DApps

Arbitrum is supported by a host of wallets and DApps, including the likes of 1Inch, Aave, Curve, SushiSwap, UniSwap, Zapper and Zerion. To check out a full list, head across to their portal.

Arbitrum Supported DApps

How to Add Arbitrum to MetaMask

To connect to Arbitrum, you’ll first need to have a wallet that supports and connects to Arbitrum. If you are using Metamask and it’s not yet available from your list of networks, follow the below guide to add Arbitrum to your Metamask account.

  • Open your Metamask web extension
  • Click onto the dropdown at the top of the wallet (if Arbitrum is not appearing in your list choose “Custom RPC”)
  • Add the following details:

Network Name: Arbitrum


Chain ID: 42161

Symbol: ETH

Block Explorer URL:

  • Click “Save” and you’ll be automatically connected to Arbitrum
How to Connect Metamask to Arbitrum

Alternatively, to integrate Arbitrum automatically, head across to the likes of Uniswap and connect your Metamask wallet. From there, you will be prompted to allow the site to add the network. Although, please always double-check these details are correct, before accepting.

To start storing Arbitrum tokens in your wallet, you’ll first need to bridge your Ethereum, ERC20 tokens to Arbitrum.

How to Bridge Ethereum to Arbitrum Layer 2

To get started using Arbitrum, you’ll need to deposit your Ethereum based tokens from the Ethereum Mainnet across to Arbitrum, using a bridge. A bridge that you can use for this process is Offchain Labs’ Arbitrum One Bridge.

If you don’t already have any Etheruem to get started with, you can purchase some on popular cryptocurrency exchanges such as Binance, FTX or Huobi with either cryptocurrency or FIAT.

  • Connect your web3 wallet (which will need to be connected to the Ethereum mainnet)
  • Select your token and enter in the amount you’d like to bridge.
  • Choose to “Deposit
  • Read the warning and terms and then choose “Deposit” when you are happy
  • Confirm within your connected wallet and pay the associated gas fee.

It may then take up to 10 minutes for your balance to appear on Layer 2.

Arbitrum Bridge to Layer 2 Ethereum

How to Withdraw Ethereum from Arbitrum to Layer 1

When bridging your tokens, it’s really important to note that there is approximately a 7 day withdrawal period. This is if you want to reverse the process and send your tokens back from Arbitrum to the Ethereum Mainnet.

How Much Are Fees On Arbitrum?

Arbitrum states that they will make interacting on the Ethereum blockchain cheaper, with fees being at a fraction of the cost of the Ethereum Mainnet. But is this true?

Well, when creating my Arbitrum tutorial, I swapped 0.5 ETH for DAI on Uniswap using both Arbitrum and the Ethereum Mainnet as a comparison. With Arbitrum the transaction cost just $2.50, whereas for the same transaction this would have cost between $30 and $39 on the Ethereum Mainnet.

How much are transaction fees on Arbitrum

Arbitrum vs Optimism

The two most competing solutions in the Optimistic Rollups space are Optimism and Arbitrum. Both Arbitrum and Optimism are Layer 2 solutions for Etheruem, created to boost speeds and reduce costs.

The main difference between the 2 is the way they generate fraud proof. Optimism, executes the whole Layer 2 transaction. Whereas Arbitrum takes a multi-round approach and executes small parts of the Layer 2 transaction until it finds a discrepancy and this enables higher transaction capacity.

Arbitrum also supports all EMV languages, including YUL, Vyper and Solidity. As opposed to Optimism wh does not support any EMV languages apart from Solidity.

Its also been said, that the codebase on Optimism is relatively minimalist, whereas Arbitrum is more complex.