What slippage actually is
Between the moment you see a quote and the moment your transaction lands on-chain, the market keeps moving. Slippage is the gap between the quoted rate and the rate you actually fill at. On a same-chain swap you wear that risk once. On a cross-chain swap you wear it twice — once on the source side, once on the destination side — which is why bridge routes quote a "minimum received" instead of a fixed number.
Minimum received: your contractual floor
When you set a slippage tolerance of 0.5%, the route carries an instruction: "fill at whatever you can get, but if the landing amount would fall below X, abort and refund." That floor is the minimum received figure on every serious quote. It turns an open-ended market risk into a bounded one — the worst case is a reverted transfer and the gas spent, never a terrible fill.
MEV and sandwich attacks
Public mempools let bots see your trade before it confirms. The classic play is a sandwich: buy just ahead of your transaction, let yours move the price, sell into your move. You fill slightly worse than fair, the bot pockets the difference. Aggregated routes counter this with private orderflow, dynamic slippage based on live volatility, and routing through pools where a sandwich is unprofitable. It's mitigated — not eliminated — which is why tolerance discipline still matters.
Setting tolerance by trade type
| Transfer type | Sane tolerance | Why |
|---|---|---|
| Stablecoin → stablecoin | 0.1% – 0.3% | Should barely move; anything above is a routing anomaly |
| ETH across chains | 0.3% – 0.5% | Deep liquidity, moderate volatility |
| Majors (ARB, OP) | 0.5% – 1.0% | Livelier price action, still liquid |
| Long-tail tokens | 1.0%+ with caution | Thin pools — consider splitting the transfer instead |
The 0% trap
Setting tolerance to zero feels safe and isn't: on any route with a volatile leg, the transfer will revert, you'll still pay source gas, and you'll retry until you learn the lesson. Zero tolerance works only on pure stablecoin corridors with fixed-rate bridges. For everything else, tolerance is a boundary you choose — not a number you minimize.
Signs your transfer got sandwiched
- Filled noticeably worse than the quote, but above your minimum — the floor held, the route just filled at the edge.
- Repeated fills at the tolerance boundary on the same pair — the pool is being farmed; try a different token pair or split sizes.
- Price impact far above what the size justifies — the destination pool is thin; check the calculator before the next attempt.
Paired with the fee breakdown, tolerance is the last lever on your all-in cost. Set it deliberately, check the minimum received every time, and treat any "too good" quote on a thin pair as the trap it usually is.
Last reviewed: September 2026.