AAuto Bridge

💻What We Made

AAuto Bridge is a solution that leverages the mechanisms of Metamask Snap and Account Abstraction (AA) to resolve the increasingly worsening bridging UX problem that accompanies the growth of Rollups. Users can smoothly complete transactions on Layer2 dApps without the need to create a new Contract Wallet or engage in bridging every time.

---

🧠Why We Made it

When a user attempts a transaction on a dApp located on a specific L2 for the first time, we can envision the following difficulties, as many users don't have ETH on Layer2 and must attempt a Cross Chain Bridge:

• Users must consider whether the Bridge is trustworthy or the best method (and never fully confirm it).
• Users must switch to the L1 network solely for the Bridge.
• Users must calculate how much ETH they might use on the specific L2 in the future (since re-bridging costs are involved).
• They feel great anxiety until the Bridge is completed safely.
• Users must switch back to the L2 network again to use the dApp.

With the increase in dApps adopting Rollups for speed improvement and lower gas costs, the aforementioned inconveniences further intensify. Users who merely want to achieve their objectives fall into a dilemma of worsening UX. This is a manifest problem that hinders Ethereum's vision of scaling to all humanity.

Efforts to solve the problem through alternatives also leave the following issues unresolved:

• Cross Rollup Bridge reduces the effort to find a bridge but does not reduce other hassles, and there are security concerns compared to native bridges.
• Smart Contract Wallets through ERC-4337 promote Gas-Less onboarding but still require a Bridge for payments, creating the new hassle of installing a wallet for Users.
• A solution is proposed in the future to procure gas and costs during tx at L2, the current dApps will not be able to perform the action because there is not enough balance before tx.

In contrast, AAuto Bridge provides the following benefits:

• Reduces the hassle of creating a new account
• Cuts the cost of searching for each native bridge on L2
• Reduces the cost of manually executing a Bridge for each L2
• No need for dApps to make adjustments, enabling immediate transactions on L2
• Deposits to L2 can be withdrawn at any time

---

👯‍♀️How it works

1. User approves the Connection Request for AAuto Bridge/Snap.
2. User sets the target network, Max Charge, and Charge Threshold.
3. User selects the amount of ETH(L1) to deposit.
4. When the user executes a transaction on an L2 dApp, the system simultaneously runs the native bridge within the set max/min, automatically replenishing the necessary ETH(L2).
5. If the user wishes to withdraw, they input the amount of ETH(L1) in Settings.

---

💭Future Works

• Extension to ZK Rollups
• Integration into Modular Account
• Further improvements to UX (reduced network switching costs, etc...)

---

Extension with MetaMask Snap and the Contract Account Manager contract:

1. When the user sets the Max/Threshold, it's saved within MetaMask Snap.
2. The user checks the balance before signing the L2 transaction.
3. If the L2 balance reaches the Threshold, a User Operation is automatically issued to execute the Native Bridge.
4. The Contract Account Manager receives the User Operation from the Entrypoint and verifies it.
5. After verification, the Contract Account Manager executes the Native Bridge with the user's L1 deposit, sending it to the L2 network specified by the user.