Vault for depositing Curve LP tokens that will harvest rewards leveraging Convex's system.
Convex has cornered the market in the context of the Curve Wars. Thus, to maximize yield on a Curve LP position, the best option is to leverage Convex's system and deposit LP tokens in their ecosystem. This allows Curve LP token holders to earn CRV & CVX emissions, along with other emissions protocols may choose to give LPs. This vault accepts Curve LP tokens, deposits them in Convex's Booster contract, & stakes them in the Convex Reward pool. Keepers are authorized by the contract owner to call the harvest() function to collect token emissions. They are incentivized with a configurable keeperFee which represents a percentage of the reward tokens. A diagram is provided below to help understand the flow.
- User can call
depositto deposit the Curve LP token & receive shares from the vault. - User can call
withdrawat any time to burn shares & receive an appropriate amount of LP tokens from the vault.
- The owner can set authorized addresses via
authorize. Authorized addresses can perform important functions such as setting Uniswap V3 swap paths. - An authorized harvester can call the
harvest()function when profitable to collect rewards. They receive a percentage of rewards (set bykeeperFee) in the form of underlying LP tokens.
This repo uses hardhat as the build & testing framework. Additionally, it also utilizes some contracts from balancer-v2, which can be downloaded via running the shell script located at scripts/load-balancer-contracts.sh. Run npm run build to build the repo & npm run test to run the test suite. The tests fork from mainnet via alchemy, and thus an alchemy api key must be exposed via an environment variable of the name ALCHEMY_KEY. A .env.example file is provided as an example.
Curve has an idiosyncratic design, and the interfaces for contracts are not identical. Thus, a small part of the logic in this vault is specific to the LUSD-3CRV pool. Notably, the add_liquidity function differs slightly for different Curve pools. However, only a few lines would need to be changed to support other Curve LP tokens. In the future, a standard interface to all Curve pools could be designed to make this more extensible.
These contracts were written in mind for Element Finance as a new yield source. A PR will be opened in the Element Finance repo, and will undergo review by Element Finance core members before being merged & deployed. Any changes there are not guaranteed to be updated here. The contracts in this repo as they are now should not be deployed to production without more thorough review.