YellFi

YellFi is a next-generation DeFi automation protocol built on Sepolia that lets users deploy ENS-named on-chain strategy agents to manage liquidity and execute trades automatically. Each agent has a readable ENS identity and runs programmable rules that interact with Uniswap v4 pools through hooks, enabling dynamic liquidity positioning, fee adjustments, and rule-based rebalancing. The Yellow SDK is used as the execution and routing layer, allowing agents to perform efficient multi-step swaps and settlements. YellFi focuses on transparent, testnet-first strategy automation, where users can create, monitor, and control named DeFi agents through a simple interface while all actions are verifiable on-chain.

YellFi is built as a modular DeFi automation stack on the Sepolia testnet using Solidity, TypeScript, and a lightweight web dashboard. The core is a Strategy Agent smart contract that stores user rules and controls execution. We integrated Uniswap v4 pool + hook contracts to enable programmable liquidity behavior such as range rebalancing and conditional swaps. ENS on Sepolia is used to mint and map human-readable subnames to each deployed agent, giving every strategy a verifiable on-chain identity. The Yellow SDK is used as the execution and routing layer, allowing agents to trigger optimized swap paths and multi-step trade flows instead of relying on a single pool. A TypeScript service listens for rule triggers and calls agent functions, acting like an off-chain coordinator for automation during testnet runs. The frontend uses a simple React + ethers stack to deploy agents, assign ENS names, and display strategy status. A notable hacky but effective piece was using event listeners plus a lightweight rule engine to simulate autonomous behavior without needing full keeper infrastructure, which kept the MVP fast and demo-friendly.