Across is a bridging protocol on Ethereum that transfers value between Mainnet and Ethereum layer-2s, and soon will connect to any EVM chain. It differentiates from other bridges by its fixation on efficient value transfer, and combination of financial and technological engineering to make the experience seamless for the end-user. In a space that has a tendency to over-engineer solutions, the protocol is refreshingly minimal in its approach while also providing strong security properties.
Across relies on relayers, who fulfill deposits for users at the destination chain the user desires. For example, let’s say a user has DAI on Ethereum but wants to use that DAI on Polygon. Using an interface on Across that’s as simple as a Uniswap trade, the user can transact that DAI from Ethereum to Polygon.
When the user submits the transaction, a relayer already with DAI available on Polygon can elect to fulfill it, and send the user the DAI minus fees on Polygon. From the user’s perspective this can lead to extremely fast fills, as the transaction to fulfill the user’s request all happens in the destination environment (in this case, Polygon), as opposed to having to hop through multiple execution environments.
From there, the user is done with the transaction, hassle-free. The relayer will get reimbursed for their time and capital by the Across LP pool, which sits on Ethereum Mainnet for maximum security. The relayer does this by submitting a proof-of-relay to UMA’s Optimistic Oracle (OO), and once the proof-of-relay is verified by the OO, then the relayer is paid out. Within the OO design, all it takes is one honest actor to dispute a relayer who is attempting to get reimbursed nefariously. So far, Across has facilitated the transfer of $1.4B+ in value for 165,000+ users without a hitch.
For people that don’t want to be active relayers, but like the idea of passively staking capital in the Ethereum Mainnet LP pools, there are attractive yields available. Below is a dashboard of yields, where we see ETH yielding ~8-22%, WBTC yielding ~5-12%, and ACX yielding ~10-29%. Across transparently displays the proportion of this yield that comes from pool fees denominated in the staked asset, versus reward fees denominated in ACX. Furthermore, the protocol has implemented an innovative feature called “Age of Capital” that amplifies yield the longer capital is committed to an LP pool, incentivizing loyalty over mercenary behavior.
Across also harnesses learnings within traditional finance, where it nets flows of funds between destination environments to avoid wasteful transfers, and bundles repayments of relayers for maximum efficiency. Therefore, the user gets maximum speed and convenience, while the relayer absorbs some of the inconvenience but gets paid for doing so.
Because Across’ design relies on financial engineering as much as it does upon technological engineering, it often provides the lowest slippage transactions of available bridging solutions, making it least costly for the user to move capital between environments. Low slippage becomes particularly impactful for large movements of value, and is another way in which Across outcompetes many of its pooled, bridging-peers.
It’s our view that the most capital efficient and secure bridges will win out over time, as other bridges chew up precious resources or lose user funds, and Across is well positioned to prove its secure and efficient design over time. While Across currently only supports Ethereum L1 and L2 movements, the expansion to other EVM environments is trivial given the design.
See you on the bridge.