In decentralized trading protocols, a solver is a specialized participant or algorithm that finds the best possible way to execute users’ trades. Instead of users trading directly against a liquidity pool, solvers compete to match orders, source liquidity from different exchanges, reduce slippage, and optimize pricing and gas costs.
Once a solver finds an efficient solution for your trade, it submits the transaction on-chain for execution. If a trade is too small or liquidity is too low, solvers may decide it is not profitable or feasible to process, which can result in the swap failing or remaining unfilled.