DAI Gets a Quick Bridge To Optimism

MakerDAO will soon launch a feature which may solve the biggest UX hangup of the Optimistic layer 2 (L2) scaling solution.

The feature will allow users to move not only DAI, but eventually any Ethereum asset, off Optimism and to layer 1 (L1) within minutes. Considering the previous withdrawal wait period of one week, the development is a major step forward in the usability of optimistic rollups.

Solving A Key Problem 

Optimitic’s current design allows for near instant transfers to its L2, but transferring back to L1 takes a week because the solution necessitates waiting for fraud proofs, which check whether all the transactions on L2 were legitimate before integrating the changes of state into L1.

The new bridge promises to solve the problem by facilitating what is essentially a week-long loan of DAI coming in the form of a token called fDAI.

But, “the user won’t have to worry about any of these details,” Sam Macpherson, the bridge’s current main developer, told The Defiant. “The interface can be as simple as swap L2 DAI for L1 DAI for a small fee.”

Under the hood, when a user withdraws from L2, they will be moving from oDAI (DAI on L2) to fDAI to DAI. fDAI will likely be an NFT because it needs to represent a specific withdrawal time from Optimistic’s L2. Unlike DAI, not all fDAI is the same.

The fDAI’s legitimacy will be confirmed by a Maker oracle which will check a transaction log called the Canonical Transaction Chain (CTC). If the fDAI is non-fraudulent a user will be able to use their new DAI on L1 within minutes from withdrawing it from L2.

More Assets On The Way

The MakerDAO proposal also outlines a mechanism by which any token will be able to be transferred from Optimism’s L2 as quickly as DAI enabled by the new bridge.

The basic functionality entails a switch from an L2 asset like ETH, into oDAI, across the bridge into L1 DAI, and then back into ETH. The proposal suggests that “AMMs (automated market makers) may want to support this directly into their UI as well.”


According to the release post the basic DAI bridge to Optimism, which entails near instant transfers from L1 DAI to L2 oDAI and normal weeklong L2 to L1 withdrawal times will be available “soon.” Optimism’s mainnet is set to go live this month.

Instant oDAI to DAI withdrawals are scheduled for Q3 or Q4 of 2021.