> ## Documentation Index > Fetch the complete documentation index at: https://pulse-hook.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Pulse Hook > Uniswap v4 hook to resist MEV using nothing but 100% on-chain Math. Frame 1 Frame 1 ## The challenge Liquidity pools *(especially low-liquidity pools on launchpads and pools for creator coins)* are highly exposed to MEV, including sandwich attacks. These strategies front-run regular users’ transactions to extract profit, often at the expense of traders and liquidity providers. The challenge is to mitigate this behavior with a solution that remains gas-efficient, fully on-chain, and independent of external infrastructure. It should not require additional nodes, off-chain oracles, or external modules. A standalone Smart Contract that can operate on any network where Uniswap v4 is available. ## The solution Pulse Hook maintains a shared median of gas priority fees across all connected pools. When a user’s priority fee significantly exceeds this median, the Hook applies an additional swap fee. As a result, sharp priority-fee spikes become increasingly expensive and can make MEV-driven transactions economically unprofitable. At the same time, the mechanism adapts to network-wide demand. If priority fees rise broadly *(for example, during a bullish market when many users compete for faster execution)* the median rises with them. The additional penalty then rapidly decreases, allowing regular users to trade without being penalized for a market-wide increase in fees. **Pulse Hook is a short name of Priority Fee Pulse Hook - the mechanism to listen to the pulse of the chain, creating a defense layer against MEV bots.** # Hook Features The main low-gas mechanism to keep up with pools activity pulse. Updates quite quickly as it is algorithmic median built using Frugal2U approach. Results in 15-blocks snapshots that keeps it even more effective. Keep the fees low for real users and high for MEV bots. Use specially created curve to punish only those who deserve it. The hook has chain-specific whitelist of chain core tokens. Median will update its state only from pools with these tokens. The second defense layer is Tick Moves Tracker that also helps to avoid small transactions aimed to move Median. Now you are welcome to [Flow & Features](/overview/e2e-flow) section where it is described step-by-step how exactly this hook works (with code snippets included). # Ready to build? Check the networks where the hook is already deployed and initialize your pool there! You can copy this hook, modify it and deploy wherever your want. This hook is MIT-licensed.