Cross-chain swap slippage: what changes between quote and delivery

Two prices define cross-chain swap slippage: the quoted output and the amount your route actually delivers. The gap measures how much execution changes after you accept the quote, often shown as a percentage or a minimum output. It matters because a cross-chain route can move through several markets before your tokens arrive.

What causes slippage in a cross-chain swap?

Slippage is the difference between the expected output in a quote and the output at execution. A swap route may trade your token into an intermediate asset, bridge that asset, then swap again on the destination chain. Each market has its own liquidity and price.

A large trade can move a pool’s price as it uses available liquidity. A thin pool or an indirect route can make that price impact larger. Price impact is the movement caused by your trade itself; slippage also includes changes between the quote and execution, such as other trades landing first.

Cross-chain timing adds another variable. The source transaction and destination action may happen in separate steps, so prices or available liquidity can change while the transfer is underway. For a case where source-chain gas affects route economics, read about Mayan Bridge routes when source gas is costly.

What does slippage tolerance protect?

Slippage tolerance sets how far the execution can move from the quoted amount before a swap step is rejected. A quote may show an estimated output and a minimum output; the minimum is the amount that step must deliver under its stated terms. The exact protection depends on how the route and its contracts apply that limit.

A tight tolerance can make a transaction fail when the market moves or the quote expires before execution. A wide tolerance gives execution more room, but it can also allow you to receive less than you expected. It does not reserve the quoted price or guarantee that every part of a cross-chain transfer will complete.

How can you compare cross-chain swap quotes?

Compare the amount expected at the destination after fees, then check the minimum output and which swap steps it covers. A route with a better headline rate may have more steps, different bridge fees or a longer execution time. The best quote is the one whose destination amount and failure conditions you understand.

• Check the estimated destination amount and its minimum, not just the source-side exchange rate.
• Look for bridge, network and service fees, and whether they are deducted from the amount shown.
• Review the route’s source and destination swap steps, especially if it uses a low-liquidity pool.
• Make sure you have the destination chain’s native gas token if you will need to move the received funds.

If a step fails, the outcome depends on the route design: a transaction may revert, or an earlier step may finish while a later swap needs separate handling. Read the route’s status and recovery instructions before retrying, so you do not send a second transaction while the first is still processing.

For most readers, a clear minimum destination amount is more useful than choosing the widest tolerance. If the quote only works with a very loose limit, compare another route or wait for liquidity to improve.