How to bridge to Arbitrum

Arbitrum is a popular Ethereum Layer 2 (L2) solution, making bridging in and out of it essential. Arbitrum uses a method called “optimistic rollup,” where smart contracts are executed off-chain and only the final output is posted to the Ethereum blockchain. It has a significantly larger transaction throughput, making it faster and cheaper than Ethereum. Arbitrum is also an Ethereum equivalent blockchain, making it easy for developers to move their applications from the Ethereum chain.

Often, blockchains are self-contained and can't communicate with other chains. Blockchain bridges exist to address this limitation. These bridges enable users to transfer their funds between different chains easily. Cryptocurrency bridges promote interoperability among blockchains and enhance the ease of transferring digital assets. The potential of decentralized applications (DApps) lies in the ability of users to easily move from one chain to another.

Preparing for bridging: wallet and asset selection

Choosing the right wallet

The first step before using an Ethereum to Arbitrum bridge is to choose the right wallet.

OKX provides a highly secure and multi-chain OKX Web3 Wallet with all OKX accounts. It can safely store ETH or any other cryptocurrency across multiple chains for as long as needed. Additionally, the OKX Web3 Wallet features bank-grade security and inbuilt access to hundreds of DApps and the OKX NFT Marketplace.

Selecting assets for bridging

To begin with, it’s necessary to confirm the asset is compatible before transferring a cryptocurrency between different chains. In this example, we'll move ETH from the Ethereum mainnet to Arbitrum One. ETH is the only requirement since it is the native currency on both networks. It's used on both the Ethereum blockchain and Arbitrum One to cover transaction fees.

To bridge a different asset like USDT, make sure that Arbitrum supports USDT. One easy way to do this is to check the bridge. If USDT is available, you should be able to bridge it. However, also make sure you have ETH on Arbitrum to pay for gas fees after you bridge the USDT.

Exploring bridge services

Decentralized bridge services

We suggest using OKX Swap as a reliable cross-chain bridge for transferring ETH to Arbitrum. By aggregating prices from various decentralized exchanges, OKX provides the most optimal route, reducing both slippage and network fees.

Arbitrum also provides its own solution, Arbitrum Bridge. However, it has a restricted range of supported cryptocurrencies and doesn't provide swapping capabilities. Other options you can check out are Meson and Stargate.

Centralized bridge services

An easy way to bridge to Arbitrum is by using centralized exchanges. This involves first transferring your digital assets to OKX on a specific blockchain, then withdrawing them on a different chain like Arbitrum.

The following guide explains how to bridge ETH from the Ethereum blockchain to Arbitrum using OKX Exchange:

Step 1: Create an account on OKX.

Step 2: After logging in, go to the "Assets" section in the top-right corner and choose "Deposit." If you don't have ETH, you can purchase some on OKX and bypass the deposit process.

Step 3: Select “ETH” as the crypto and “ETH-ERC20” as the deposit network.

Step 4: Transfer ETH to the provided address. It may take a few minutes for the ETH to arrive in your account and become available.

Step 5: After your funds are available, head back to the "Assets" section and choose "Withdraw."”

Step 6: Choose "ETH" as the cryptocurrency and opt for "On-chain" as the withdrawal option.

Step 7: Type in your Arbitrum address and select the network as “ETH-Arbitrum One.” Enter the amount of ETH you want to bridge to Arbitrum and hit next. After verifying your account, the ETH will be deposited into your wallet in a matter of minutes.

One convenient method for transferring your assets is through an exchange, as it removes the concern for slippage and network fees.

Choosing a bridge service

Both centralized and decentralized cryptocurrency bridges are good choices. Decentralized bridges, in particular, allow for quicker movement between chains. However, they do have drawbacks, such as high fees and slippage. It's essential to prioritize security when selecting a decentralized bridge and opt for a well-established one with a proven track record.

Bridging process: a step-by-step guide

To bridge ETH to Arbitrum, you'll need to link your wallet to the bridge and transfer your assets. We'll be using the OKX Web3 Wallet and OKX Swap for this process, but it should be similar if you prefer to use a different wallet or bridge service.

Connecting to a bridge service

Step 1: Head over to OKX Swap.

Step 2: Choose "Connect wallet" located in the upper right corner, then opt for "OKX wallet extension". Or, if you prefer to use a different wallet provider such as Metamask or Phantom, select "Other" and choose your preferred wallet.

Step 3: To connect your OKX wallet and OKX Swap, enter the password for your OKX wallet, and then select "Confirm".

Transferring assets to Arbitrum One

Once you’re connected to OKX Swap, you’re ready to bridge ETH to Arbitrum.

Step 1: Adjust the bridge settings and specify the quantity of ETH you wish to bridge in the "Swap & Bridge" section.

1. Select “Ethereum” as the “from” chain and type in the amount of ETH you want to bridge.

2. Select “Arbitrum” on the “To” chain and token “ARB_ETH.” OKX Swap will automatically show you the amount of ETH you’ll get.

Step 2 (optional): This step isn't required, and we recommend you only complete it if you understand slippage and bridges well.

1. Network fee: This calculates the Ethereum network's cost for bridging.

2. Slippage: Slippage refers to the level of flexibility you’re willing to allow for price fluctuations. By setting the slippage to 0%, OKX swap guarantees you'll receive exactly 0.49872 ETH, as indicated. The transaction will be voided if the price fluctuates, and you'll be charged a network fee. Allowing for some slippage is important when the pool has limited liquidity.

3. Trading route: OKX Swap isn't a bridge but rather a DeFi aggregator that automatically selects the most suitable bridge to Arbitrum for you. However, you have the option to manually change the service if wanted.

Step 3: Select “Swap across chains.” When your wallet pops up, confirm the transaction.

OKX Swap is a convenient DeFi tool to get your cryptocurrencies across bridges and swap them along the way.

OKX Swap and other bridges can serve as bridges between Arbitrum and ETH in both directions. To perform an Arbitrum to ETH bridge, the primary network must be selected as Arbitrum and the secondary network as Ethereum.

Understanding fees and timelines

Fee structures explained

There are multiple fees involved in a decentralized bridging process:

1. Ethereum gas fees: To use OKX Swap and send your ETH, you must pay a transaction fee to the Ethereum network.

2. Bridge fees: OKX Swap acts as a hub for connecting bridges. As part of the bridging procedure, a small charge is imposed by the bridge.

3. Arbitrum transaction fees: Similar to the gas fee on Ethereum, a transaction fee is imposed on Arbitrum to enable the transfer of ETH from the bridge to your Arbitrum wallet.

4. Conversion fees: There's an extra charge when you bridge between cryptocurrencies. For example, if you want to send USDT from Ethereum but want to receive ETH on Arbitrum, there willl be a fee for converting USDT to ETH.

Before the transfer, you can check the conversion and bridge charges using OKX Swap. However, the Ethereum gas fee will only be visible in the OKX Web3 Wallet pop-up when verifying the transaction.

Expected transaction times

Just like the fee involved, transaction time also depends on multiple factors:

1. Ethereum confirmation time: The duration it takes for ETH to move from your wallet to the bridge is dependent on the amount of gas used. With sufficient gas, the process should only take a few seconds.

2. Bridge processing time: The duration of asset transfer between chains varies depending on the bridge being used. For OKX Swap, the trading route can be viewed in advanced options to determine its time.

3. Arbitrum blockchain confirmation time: Once the bridging process is complete, the ETH will be sent to your wallet. With Arbitrum's efficient processing speeds, it should reach your wallet almost instantly.

Security measures and best practices

Securing your transactions

When using a cryptocurrency bridge, it's important to remember that you’re interacting with a smart contract that can access your wallet. It's possible for malicious smart contracts to withdraw funds from your wallet without your awareness. For safer crypto transactions on bridges, we recommend the following.

1. Make sure you’re using a trustworthy bridge with a proven track record in the market.

2. Avoid using your primary wallet to engage with bridges and other decentralized applications. Keep a separate cold wallet for storing your assets.

3. Use tools like Revoke to block access to your wallet once bridging is complete.

An effective approach for minimizing these dangers is to use a centralized exchange for bridging purposes. As a leading global cryptocurrency exchange, OKX employs world-class security measures to protect users and allow them to buy and sell BTC safely and seamlessly. Visit our security of funds and Proof of Reserves page for more details.

Avoiding common pitfalls

Here are some of the common pitfalls you can avoid while you’re bridging your assets to Arbitrum:

1. Make sure to review all the information you enter before submitting it. Once you confirm the transaction, there's no option to reverse it.

2. Be mindful of the gas fees. When the Ethereum network is congested and in demand, ‌gas fees may rise. You can either wait for the fees to decrease or use a centralized exchange to bridge.

3. High slippage and liquidity issues are another aspect to look out for. Using a bridge that isn't well-known or bridging to a coin with low trading volume may result in significant slippage. To prevent this, use bridges for assets with abundant liquidity.

Troubleshooting and support

Common bridging issues and solutions

1. Many users struggle with transactions getting stuck due to insufficient gas fees. In congested situations, transactions may also get stuck on bridges, but they're designed to handle this and will eventually be resolved. Just be patient and wait.

2. Cross-chain compatibility: Before bridging, make sure the asset you’re using has sufficient liquidity and is compatible with the chain.

Where to find support

It’s usually not difficult to find support in the crypto community should you encounter any problems.

If you have issues with OKX Swap or Exchange, visit OKX Support for FAQs and chat with the team for help. Always use official support resources and watch out for scams.