Zeur
Zero-Interest Loan Protocol with AI agent
Demo
About
The problem it solves ## The Problem We Solve Many crypto holders, particularly in Europe, view their assets as long-term investments. They don't want to sell, which would trigger a taxable event and cause them to miss out on potential future appreciation. However, they often need cash for major life purchases like a down payment on a house, a car, or other significant expenses. Their current options are very limited for real world spending: 1. **Borrow from DeFi (Aave/Compound):** Traditional DeFi lending has variable, often high-interest rates that can exceed standard consumer loans (which are ~4-7% in Europe). This makes borrowing for real-world expenses unpredictable and potentially expensive. 2. **Borrow from TradFi (Consumer/Mortgage Loan):** While rates can be lower (~3-5%), the process is slow, requires extensive paperwork, and doesn't recognize crypto as collateral. 3. **Use other "Zero-Interest" Protocols:** Services like Alchemix or Liquity are innovative but force borrowers to take out loans in a new, protocol-specific stablecoin (like alUSD or LUSD ). These stablecoins lack the liquidity, trust, and direct off-ramps to be easily converted into Euros and used for real-life purchases. ## The Idea: A Zero-Interest Loan Protocol Our protocol is a decentralized lending platform where users can borrow real-world value against their crypto assets without paying any interest. Borrowers deposit yield-generating collateral like ETH (Ethereum), LINK (Chainlink ), AVAX (Avalanche), and in return, can borrow established, fiat-backed stablecoins like EURC. Instead of charging borrowers interest, their collateral is automatically put to work in trusted, low-risk yield strategies (stable, organic yield from Lido, Ether.fi, RocketPool, etc.). The entire yield generated from this collateral is used to pay interest to the lenders who provided the EURC. ## Architecture  - Pool: entry contract for users (supply, withdraw, borrow, repay, liquidate) - Vaults: manage user deposited asset through Pool, interact with routers to stake asset in LST protocol. - StakingRouter: plug-and-play contract that have the same interface, but different logics for each LST protocol (Lido, Etherfi, RocketPool, StakeLink or lending like Morpho) - Tokenization: ColEURC/DebtEUR represent the user's supply/debt of EUR stablecoins, ColToken represents the user's collateral - ChainlinkOracleManager: to get price of asset through Chainlink price feeds - VaultManager: dedicated contract with harvest/distribute yield and rebalance portfolio logics - Chainlink Automation: time-based keeper that execute distribute yield - ElizaOS: offchain "brain" to monitor position, create strategy, execute rebalance ## Chainlink Technology The protocol’s security and automation rely on the full Chainlink stack: - Chainlink Price Feeds deliver real-time asset prices for safe LTV calculations, borrow/withdraw limits, and liquidations in the Pool contract. [ChainlinkOracleManager](https://github.com/zeur-org/zeur-core/blob/master/src/chainlink/ChainlinkOracleManager.sol) [Pool](https://github.com/zeur-org/zeur-core/blob/master/src/pool/Pool.sol) - Chainlink Automation runs scheduled yield-harvest and distribution cycles, keeping payouts transparent and on time. [ProtocolVaultManager](https://github.com/zeur-org/zeur-core/blob/master/src/pool/manager/ProtocolVaultManager.sol) - Chainlink Staking lets users post staked LINK as collateral, adding a new utility layer for the LINK community while reinforcing network security. [VaultLINK](https://github.com/zeur-org/zeur-core/blob/master/src/pool/vault/VaultLINK.sol) [StakingRouterLINK](https://github.com/zeur-org/zeur-core/blob/master/src/pool/router/StakingRouterLINK.sol) ### Key Features 1. **Zero-Interest Borrowing:** The core value proposition. Borrowers' debt does not grow over time. 2. **Yield-Forwarding Mechanism:** The protocol automatically deploys collateral into audited, blue-chip yield strategies. The harvested yield is then converted and paid directly to EURC lenders. 3. **Fiat-Backed Stablecoin Focus (EURC):** We use established, regulated stablecoins. This ensures immediate real-world utility, high liquidity, and straightforward on/off-ramping for users. 4. **Automate Yield distribution:** We use Chainlink Automation to automate distributing yield to ERC4626 Vault. ### Smart contracts & Deployments [Documentation](https://zeur.gitbook.io/zeur) [Core Contracts](https://zeur.gitbook.io/zeur/contracts) [Ethereum Sepolia deployments](https://zeur.gitbook.io/zeur/deployments/ethereum-sepolia) [Avalanche Fuji deployments](https://zeur.gitbook.io/zeur/deployments/avalanche-fuji) [Smart Contract Repo](https://github.com/zeur-org/zeur-core) [Interface Repo](https://github.com/zeur-org/zeur-interface) [ElizaOS Repo](https://github.com/zeur-org/zeur-elizaos)
How it's made
Challenges we ran into **1. Integrating multiple liquid-staking protocols:** - **The Hurdle:** Our protocol's core value proposition is generating yield from various Liquid Staking Tokens (LSTs). We quickly realized that a "one-size-fits-all" integration was impossible. Each major protocol—Lido (stETH), Ether.fi (weETH), RocketPool (rETH), and StakeLink (stLINK)—has a completely different set of smart contracts, function calls, and mechanisms for staking, unstaking, and reward accrual. A naive integration would have resulted in a rigid, unmaintainable system that would break with any upstream protocol update. - **How We Overcame It:** We designed a modular and extensible "Vault-and-Router" architecture. - Asset Vaults: Each collateral type (e.g., ETH, LINK) is managed by its own dedicated vault contract, isolating the assets. - Staking Routers: For each LST protocol, we created a specific 'Router' contract. All routers conform to a standardized IStakingRouter interface, but the internal logic is tailored to the target protocol (e.g., a LidoRouter, an EtherfiRouter). - **Result:** This design gives us a plug-and-play framework. To support a new LST in the future, we only need to deploy a new, compatible router contract without altering the core protocol logic. This makes our system highly scalable and resilient to changes in the liquid staking ecosystem. **2. AI for on-chain Yield Optimization** The Hurdle: We initially aimed to use an on-chain AI agent (exploring ElizaOS) to autonomously optimize our yield strategies. We discovered that the non-deterministic nature of AI created a significant security risk for our deterministic smart contracts, potentially leading to unpredictable fund allocation and exploits. How We Overcame It: We pivoted to a hybrid model. The AI now acts as a powerful off-chain analytics engine that analyzes market data and proposes strategy changes. These changes are bound by predefined portfolio constraints, which help to have more predictable outcomes.