Set a Destination Minimum for a Cross-Chain Swap

Set a destination minimum by converting the quoted output into the least amount of the destination token you will accept after the destination swap. That floor gives the route room to execute while rejecting a swap that returns too little.

What does a destination minimum protect?

It protects the output amount, not the amount sent on the source chain. A cross-chain route may bridge an asset, then swap it on the receiving chain; each stage can add fees or face changing liquidity and prices.

LI.FI’s quote documentation distinguishes an estimated output, toAmount, from toAmountMin, the guaranteed minimum for the transfer including slippage. A fuller walkthrough of a Paraswap cross-chain swap flow shows where the destination swap fits; the key is to set the floor against the final token the recipient should receive.

How do you calculate the floor?

Start with a fresh route quote for the exact source amount, destination token and recipient. If the quote gives expected output Q and your allowed slippage is s, a simple minimum is Q × (1 − s); use the route’s own minimum-output field when it accounts for fees and execution details.

Before signing, check these values in the same token units the destination contract expects:

• Confirm the destination token’s chain and contract address.
• Read its decimals and express the minimum in base units.
• Check whether the quote’s output is before or after destination fees.
• Compare the route’s minimum with the amount you need to receive.

For example, if a quote estimates 100 destination tokens and the chosen tolerance is 1%, the simple floor is 99 tokens. That calculation is only sound if 100 is already the net output; subtracting fees twice makes the floor unnecessarily strict.

How much slippage should you allow?

Choose the narrowest tolerance that still lets the route execute under expected price movement. A tighter floor can cause a destination swap to fail when the market moves; a looser floor accepts a worse rate, so it should not be used just to make a transaction appear more reliable.

Check what happens if the bridge completes but the destination swap cannot meet its minimum. Recovery, refunds and manual claims depend on the route and protocol, so verify the documented failure path before sending funds. The next step is to submit the route with the reviewed minimum; the final delivered amount and any failure recovery remain unconfirmed until execution completes.