Set cross-chain slippage against each swap leg

Set cross-chain swap slippage from the minimum output the route promises on each swap leg, then use the tightest tolerance that lets those legs execute reliably. A single percentage is only a limit on price movement under a particular contract or route; it is not protection against bridge delays, fees, or every kind of execution failure. Before signing, check which leg the setting applies to and what happens if that leg cannot meet its minimum.

What does slippage tolerance control in a cross-chain swap?

Slippage tolerance sets how far execution may move against the quoted price before a swap reverts or fails its stated condition. In a constant-product AMM, the swap contract checks the output against a minimum amount, often called amountOutMin. If reserves change before execution and the calculated output falls below that minimum, the contract reverts the swap. A looser tolerance lowers the minimum and permits a worse execution price.

That limit is distinct from price impact. Price impact is the change in the quoted price caused by the trade’s size against available liquidity; slippage is the difference between the quoted and executed price. A route can have high price impact before submission and little subsequent slippage, or a modest initial price impact and still move before execution. Fees and bridge costs also reduce what arrives, but they are not slippage unless the interface specifically includes them in the quoted output.

A cross-chain route may contain a source-chain swap, a bridge or messaging step, and a destination-chain swap. Each component has different execution conditions. The source swap may use an on-chain minimum-output check, while the destination leg may use a separate transaction, a solver’s fill commitment, or another protocol-specific rule. Read the route details to identify whether the displayed tolerance applies to one leg, multiple legs, or an overall destination amount.

How should I choose a tolerance for each leg?

Start with the route’s quoted minimum output and the smallest tolerance the interface permits. Check whether each leg has its own minimum and whether the displayed destination amount is a firm bound or an estimate. Comparing routes helps: a route with deeper liquidity or fewer market swaps may need less slippage headroom. For the wallet-side steps behind that comparison, see how to choose a Quickswap route. The relevant question is not which route has the most hops, but what each hop contributes to the final minimum.

Then consider execution conditions. A trade routed through a thin pool is more sensitive to another trade landing first. A long confirmation delay or volatile market gives the quote more time to become stale. Those factors may justify a wider bound, but widening it also accepts a worse fill. If the route repeatedly fails at a tight tolerance, first check whether the quote refreshed and whether a deeper route or smaller trade improves the minimum. Raising the tolerance should be a deliberate response to the expected movement, not a generic fix for failed transactions.

Use these checks before signing:

• Identify the source and destination swap legs, and note each quoted output and minimum.
• Check whether bridge fees, relayer fees, and destination gas are already deducted from the displayed amount.
• Compare the route’s liquidity and number of market swaps, then refresh the quote immediately before submission.
• Confirm the failure outcome: revert, refund, retry, or a claimable asset can have different costs and timing.

What can go wrong after the source swap?

A source transaction can succeed while the destination leg does not complete as quoted. The bridge may deliver later, the destination market may move, or an executor may be unable to satisfy the destination minimum. The result depends on the protocol’s settlement design. Some routes revert the relevant swap and return funds through a defined recovery path; others can leave the user with an intermediate token or require a separate claim or retry. A source-leg slippage setting does not guarantee a particular destination output unless the route explicitly binds that outcome.

Bridge latency is not itself slippage. It creates a longer interval in which the destination quote may change, but the bridge and swap contracts determine what happens when it does. Check whether the destination amount is guaranteed, conditional on a minimum, or merely estimated. Also check whether a failed destination execution returns the original asset, the bridged asset, or another token, and who pays any retry or recovery transaction costs.

When should I widen the setting or reduce the trade?

Widen the tolerance only when the route’s market movement plausibly exceeds the current bound and the quoted minimum remains acceptable to you. A higher tolerance trades a lower chance of a slippage-triggered failure for a larger range of permitted execution prices. It cannot prevent a bridge outage, guarantee settlement, or correct a misleading quote.

If acceptable execution requires a bound so loose that the minimum output is unattractive, reduce the trade size or choose a route with deeper liquidity. For most swaps, the better setting is the narrowest one that accommodates the route’s expected execution movement while preserving a minimum output you are willing to receive. If the interface does not show which leg that setting protects or how failed destination execution is recovered, the percentage alone is not enough information to assess the route.