> For the complete documentation index, see [llms.txt](https://docs.dittonetwork.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.dittonetwork.io/ditto-usd-meta-lending/architecture.md).

# Architecture

The system operates on a trust-minimized architecture separating **Decision Making** from **Execution**:

1. **Ditto Keeper (Off-chain)**: Monitors yield opportunities 24/7.
2. **APR Oracle (On-chain)**: Snapshots realized APRs from underlying protocols to prevent manipulation.
3. **Rebalancer (On-chain)**: A stateless contract that calculates the optimal split of funds to maximize APY.
4. **Vault (ERC-4626)**: Atomically executes deposits/withdrawals across strategies.

#### Security Measures

* **Non-Custodial**: User funds are held in the smart contract, never by Ditto or the integrator.
* **Atomic Execution**: Rebalances happen in a single transaction.
* **Slippage Protection**: The vault snapshots Total Value Locked (TVL) before and after every rebalance.
* **Reward Debt Model**: Protocol fees are minted exclusively from yield. The principal deposit is never touched.

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