Auto HODL

[auto-hodl.vercel.app](https://auto-hodl.vercel.app/)

**Auto HODL** is Acorns.com for your MetaMask Card. 
Auto HODL enables users to **automatically save** USDC while spending using their **MetaMask card**. 
It works by **rounding up** each transaction to the nearest dollar and sending the spare change to a **savings account** — effortlessly building a crypto savings habit.

Some of the features include: 

- Round up payments to the nearest USDC dollar and send the change to AAVE.
- MetaMask SDK for wallet connect.
- MetaMask DTK/DeleGators for protecting users funds. The protocol can only send up to your round-up amount.
- Realtime multi-chain Aave yield optimization.
- Cross chain with LiFi/CCTP v2.
- Circle Modular Wallets for custody.

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## 🏗️ Hackathon Demo Modes

During the [MetaMask Card hackathon](https://www.hackquest.io/hackathons/MetaMask-Card-Dev-Cook-Off) we shipped two working prototypes and sketched a third, future-ready design:

### 1. Single-chain (hackathon)

![Single-chain Mode](https://github.com/locker-labs/auto-hodl/blob/93467ae7d29651b0fab2296aba98281558dd1b2f/docs/01-mode-single-chain-hack.png)

End-to-end flow on Sepolia. Every MetaMask Card purchase is rounded-up and the difference is supplied to the Aave pool on the same chain.

### 2. Multi-chain (hackathon)

![Multi-chain Mode](https://github.com/locker-labs/auto-hodl/blob/645d76f8e2d1c9f0bbb61b3bebab4f53758c05c1/docs/03-mode-multi-chain-hack.png)

At round-up time the backend finds the best Aave yield, bridges funds via **LiFi/CCTP**, and supplies on the destination chain.

### 3. Single-chain (future)

![Future Single-chain](docs/02-mode-single-chain-future.png)

Planned production upgrade:

* Use Linea. Cannot be used now becuase DTK/DeleGator not yet compatible with Linea.
* Use **native smart accounts** instead of explicit DTK deployment.
* Request delegated permissions with **ERC-7715**.
* Use the underlying EOA (connected to the card) as the savings source.
* Use Circle Gateway for instananeous bridging.
* Batching funds before bridging or depositing into Aave, to reduce the impact of fees.

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## Implementaiton details
Here is a rundown of some of the most important implementation details:
- Triggered by [deposits to MM Card](https://github.com/locker-labs/auto-hodl/blob/93467ae7d29651b0fab2296aba98281558dd1b2f/apps/web/src/lib/constants.ts#L5) contract.
- [Delegations](https://github.com/locker-labs/auto-hodl/blob/93467ae7d29651b0fab2296aba98281558dd1b2f/apps/web/src/hooks/useMetaMaskDTK.tsx#L174) to give protocol access to user funds.
- [Caveats](https://github.com/locker-labs/auto-hodl/blob/93467ae7d29651b0fab2296aba98281558dd1b2f/apps/web/src/lib/utils.ts#L12) to ensure only USDC is spent, and only up to the round-up amount.
- [Creation](https://github.com/locker-labs/auto-hodl/blob/93467ae7d29651b0fab2296aba98281558dd1b2f/apps/web/src/lib/circle/createSmartAccount.ts) of Circle Modular Wallets for cross-chain savings.
- [LiFi/CCTP v2](https://github.com/locker-labs/auto-hodl/blob/93467ae7d29651b0fab2296aba98281558dd1b2f/apps/web/src/lib/lifi/index.ts) integration.
- Aave [yield optimization](https://github.com/locker-labs/auto-hodl/blob/93467ae7d29651b0fab2296aba98281558dd1b2f/packages/scripts/find-optimal-yield.ts).
- Sample [trigger address](https://arbiscan.io/address/0xF445b07Aad98De9cc2794593B68ecD4aa5f81076)
- Sample [source of funds](https://arbiscan.io/address/0xc8f20aa6Ac3650241a88f0e4300ca988EfDc241F) (delegator)
- [Protocol delegate](https://arbiscan.io/address/0x4D769e03B8D068147B6aF4935F8fE419Cfd03784)