Swap aggregators: why you need a middleman between you and a hundred DEXes

DeFi's liquidity is smeared across hundreds of pools and dozens of protocols. The aggregator is a router that assembles your swap from pieces at the best combined rate.

What the aggregator optimizes

• The route: it splits the order between pools (30% here, 70% there) and builds multi-hop paths through intermediate tokens - on illiquid pairs the win reaches percents.
• The whole price: good aggregators compute the net result after gas and fees, not the pretty pre-trade rate.
• Protection: MEV protection, simulating the transaction before sending, honest minimum-received math.

When a direct swap is better

On ultra-liquid pairs with one dominant pool an aggregator can add gas for extra hops with no rate win. And aggregators have their own risks: one more contract in your trust chain (its approvals are separate hygiene) and the positive slippage some routers keep for themselves.

In practice: exotics and size - always through an aggregator with route comparison; a routine majors swap - wherever is factually cheaper, gas included. And regularly revoke old approvals - routers accumulate them for years.