acrossbridge can move ETH from Arbitrum to Ethereum in seconds to minutes on a supported route, while a canonical withdrawal normally takes seven to eight days. If your Ethereum app needs funds now, acrossbridge offers a faster exit at a quoted cost. Across Bridge uses relayer liquidity; a canonical withdrawal waits for the rollup’s challenge period and then requires a claim.
How Do the Two Rollup Exits Work?
A fast exit pays you from a relayer’s funds on Ethereum before the Arbitrum withdrawal process finishes. You specify the token, amount, destination chain and recipient; the bridge shows how much the recipient will get. When you confirm, your tokens enter a smart contract on Arbitrum, and a relayer fills the transfer on Ethereum using its own tokens.
The relayer is repaid later, after the protocol checks that its fill matches your deposit. That background settlement is why you can use the received ETH without waiting a week. The service is non-custodial in the sense that you sign from your own wallet, though the deposited funds are held by a smart contract during the transfer.
A canonical withdrawal follows Arbitrum’s native exit path. You start the withdrawal on Arbitrum, wait for its roughly 6.4-day challenge period, then claim the ETH on Ethereum after the withdrawal becomes executable. The full process commonly takes seven to eight days. It uses the rollup’s withdrawal mechanism rather than a relayer advancing funds.
The security trade-off follows those mechanics. A fast exit depends on bridge contracts, available relayer liquidity and the protocol’s checks on repayment; a canonical exit depends on Arbitrum’s rollup and bridge contracts. A fast fill also does not make the underlying rollup withdrawal finalize sooner.
What Will Each Exit Cost and How Long Will It Take?
The fast route usually takes seconds to minutes after your Arbitrum transaction is accepted, but its fee changes with the route. The quote includes the relayer’s destination gas and capital costs, plus any liquidity fee; you also pay Arbitrum gas to start the transfer. Check the displayed amount received, because a percentage alone may miss part of the cost.
For example, say you send 0.5 ETH and the quote delivers 0.4985 ETH on Ethereum. The difference is 0.0015 ETH, or 0.3%, before your Arbitrum transaction gas. That is an illustration, not a standing rate: Ethereum gas, route demand, token liquidity and transfer size can change the next quote or make an instant fill unavailable.
A canonical withdrawal has no relayer spread. You pay gas to initiate it on Arbitrum and gas again to claim it on Ethereum; the Ethereum claim cost can change substantially while you wait. If you can leave the funds untouched for a week, compare those two gas estimates with the fast route’s total cost before choosing.
Which Route Should You Use for This Transfer?
Choose by deadline, token and final amount received. Suppose you have ETH on Arbitrum and need to fund an Ethereum app this afternoon: check that the Across crypto bridge offers Arbitrum-to-Ethereum ETH for your amount, then read its estimated arrival time and output. If that output covers the app’s deposit and Ethereum gas for your next action, the fast route meets the deadline that a canonical withdrawal cannot.
For an ERC-20 token, check its contract address on both chains and confirm the app accepts the destination version. Tokens with similar names can have different issuers or bridge histories, and a successful transfer does not guarantee the app will accept what arrives. Also check the quote’s minimum and maximum amount: a thin route may offer a slower fill or no quote for a large transfer.
If you choose the fast route, verify the recipient and minimum received before signing, then track the deposit until the destination fill appears. If you choose the canonical route, keep the withdrawal record and return to claim it once the waiting period ends; leave enough ETH on Ethereum for that claim. Make those checks now, then submit the route whose arrival time and received token fit your task.