Set minOut at the destination for cross-chain swaps

A trader sets minOut before signing a cross-chain swap to define the least destination tokens the route may deliver; on a quote of 100 tokens, a 1% tolerance sets a 99-token floor. That floor gives the transaction room for price movement while rejecting execution below the amount the trader accepts.

What does minOut protect in a cross-chain swap?

minOut is a floor on received output, not a promise that the quoted amount will arrive. Across’s Swap API distinguishes an exact-input request, which spends a fixed input and calculates output after fees and slippage, from minOutput, which specifies the output floor; LI.FI’s quote documentation likewise defines toAmountMin as the guaranteed minimum including slippage.

On a cross-chain route, the final amount can reflect swaps, bridge fees and exchange-rate changes across more than one chain. Check that the floor refers to the destination token and the full route, rather than an intermediate swap on the origin chain. For stalled swaps caused by route choice, see choosing a quickswap route when a swap stalls.

How should you choose a safe minOut?

Start with the route’s final quoted output, then set the minimum at the lowest amount you would still accept after price movement and stated fees. A larger slippage allowance lowers that floor and makes execution more likely as prices move, but also lets the trade complete at a worse rate.

• Confirm the quote’s output token and destination chain.
• Use the final-route minimum, including applicable fees, rather than a midpoint or an origin-chain estimate.
• Choose a tolerance that reflects the asset and route’s expected price movement; do not widen it just to force a failing trade through.
• Review the transaction details to confirm the minimum is actually enforced.

There is no universal safe percentage: a stable, liquid pair and a volatile or thin route can move differently. The 1% example above is arithmetic, not a recommended setting.

What happens if the route misses the floor?

If the transaction enforces minOut and the route cannot meet it, execution should fail or use the provider’s stated refund or recovery path; the exact behavior depends on the bridge and swap design. Across’s documentation describes minimum-output and refund options, while LI.FI describes a minimum transfer amount in its quote response.

Before signing, compare the destination minimum with the quote and check the provider’s failure handling. After submission, follow the route’s status until settlement; the final received amount and any recovery action remain unconfirmed until the destination transaction completes.