How I Slashed Gas Costs by 25% for a Solidity Merkle Mixer

The author optimized a Solidity-based Merkle privacy mixer on Base, reducing average gas costs from 72,332 to 53,897 (roughly 25%). Key techniques included packing nullifiers into bitmaps instead of bool mappings, using calldata instead of memory for Merkle proofs, and replacing require strings with custom errors.