You have a stack of USDC on zkSync, you need it on Base inside ten minutes, and the bridge UI is quoting you 0.12% plus a $4.40 fixed fee. That is the moment you start looking at the L2-native routes. After two years of routing through the same handful of pools, here is where the math actually lands in late August.
Syncswap is still the cheapest Layer 2 DEX route for the common USDC/USDT pair on zkSync Era. On a $25,000 swap at typical pool depth, the round-trip cost is around 4.5 bps all-in: 3 bps from the pool fee, the rest slippage on a tight 0.05% routing tolerance. The equivalent on the next-cheapest venue runs closer to 9 bps once you factor in the extra hop their router adds to dodge thin pools. Over a quarter of moving $1M through, that gap is roughly $450 you keep or hand to a market maker.
Two things to watch before you size up. First, the classic pool is the one you want; the stable pool contract uses a different curve and quotes worse on anything under $50k. Second, slippage tolerance. 0.05% is the sweet spot for the deep USDC/USDT/USDC.e trio. Set 0.5% and you are donating. Set 0.01% and you will revert on routine pool updates.
One quirk worth knowing: Syncswap's router does not always pick its own pool. On multi-hop routes it will occasionally route through a thinner pair when a more liquid two-hop is available. If the quoted output looks generous, check the path. Manually splitting the trade across two direct swaps is sometimes cheaper than letting the router try to be clever.
If you are routing size on zkSync today, the working assumption is that syncswap eats the lunch of the older order-book DEX and the routing aggregators for the staple pairs. That has been true for about nine months running, and nothing on the fee schedule or the pool depth charts suggests it changes before the next network upgrade.