Nebula - Metis Lending Protocol

Inspiration

Metis ecosystem is ready to have consistent lending protocol, the one which can connect several protocols and ready to be integrated into the DeFi ecosystem. Also, the protocol should be built by the team which have the experience in DeFi and blockchain technologies. That is why Nebula is presented - lending protocol, ready for integrations and capable to be expanded up to even crosschain operarions.

What it does

Nebula provides a money market, where suppliers are able to earn interest on their deposits, where borrowers are able to borrow assets for variable rate, where they don’t specify any time frames, or borrow for fixed rate, where borrowers provide maturity, until which they have to repay a loan.

So, regular loans (already built into the platform) are well-known. The protocol supports supply/withdraw, borrow/repay operation so as the liquidation process. The main interest is for fixed-rate loans. Nebula allows a user to borrow assets for a fixed rate for a specific period of time. There are two conditions, which have to be met, before borrowing: providing a respectful amount of collateral and specifying a maturity period. Currently, the loans for 1, 2 and 4 weeks are available. The protocol calculates interest, based on the variable rate at the moment of borrowing, and guarantees that rate won’t be changed during the maturity period. After the maturity is reached, a borrower should repay his loan during the next rest period(currently 4 hours) plus interest. Borrower is also able to repay his loan before maturity is reached, paying interest, calculated based on the fixed rate and time elapsed since borrowing. Borrower also has to pay a small extra interest for repaying before maturity is reached.

How we built it

Protocol is built with Solidity and deployed into the Metis Testnet. We gathered the experience from work with landing platforms (like Compound or Aave, etc) in order to create more lightweight platform, with less expensive integration of fixed-rate loans and (in perspective) improved DAO.

Challenges we ran into

First of all - a slight difference between deployment and verification of the contracts on Eth/BSC/Polygon and on Metis. After that - work on gas optimizations. Though the main challenge was contracts verification, which did not work for the testnet. So as several contract calls to the available nodes.

Accomplishments that we're proud of

We have provided all necessary contracts and operations:

• two markets (for the beginning) - for emulations of USDC and Metis token
• easy way to add more markets
• core operations (including liquidation) for float-rate pools
• fixed-rate loans mechanic with their liquidation mechanism
• collaterization calculations kept for all markets
• optimized gas usage
• full deployment on the Stardust testnet https://github.com/Nebula-Lending/nebula-protocol/blob/main/scripts/deploy_script/deploy_info.json
• full set of contract calls and scenarios for interacting with the protocol https://github.com/Nebula-Lending/nebula-protocol/tree/main/scripts

What we learned

The main what we have learnt - the Metis ecosystem, how Metis chain works, what are differences for deployment and other contracts-connected operations.

What's next for Nebula - Metis Landing Protocol

Roadmap actually is very huge: 1) Expand the protocol to get more markets 2) Add new interest rate model 3) Add whitepaper 4) Add DAO for the protocol governance 5) Add internal incentives in native tokens 6) Add active management of the locked funds 7) Add integrations with Metis DeFi ecosystem for yield farming strategies integration for pools rebalancing and for better rewards mechanisms. 8) Cross-chain operations - TBD, though core developers of the protocol have won the Near hackathon with the unique landing platform for Near protocol. Thus, there is an option to expand the ecosystem.

Built With

• brownie
• javascript
• solidity
• truffle