Slippage tolerance sets the worst price a swap will accept before it fails. In a cross-chain transfer, a swap can happen before or after the bridge moves your assets, so a delay or thin liquidity can push either swap past its limit. Knowing which leg failed helps you decide whether to wait, retry, or change the trade.
What does slippage tolerance protect?
It sets a minimum amount you must receive for a swap to go through. Slippage means the difference between the expected swap price and the price available when the trade executes; ETHGlossary describes the tolerance as a way to make a trade revert instead of filling at a much worse price.
For example, a quote might estimate 0.40 SOL for your input. With a 1% tolerance, the swap may accept as little as 0.396 SOL; below that, its minimum-output check fails. That limit protects your price, but it does not guarantee the quote will still be available later.
A cross-chain route can include a source-chain swap, a bridge transfer, and a destination-chain swap. The bridge transfer carries assets or a message to the destination chain; each swap can have its own execution point and protection. A delay, a price move, or low liquidity on either chain can cause the relevant swap to miss its minimum.
How should you choose a tolerance?
Choose the narrowest tolerance that still fits the route’s likely price movement. A small tolerance limits how much worse the swap can execute, but a busy network, volatile token, long bridge delay, or shallow liquidity can make a quote stale before the destination swap runs.
Suppose you often move a stablecoin and swap it for SOL. If the quoted destination output is 0.40 SOL and the route allows 1%, a move below 0.396 SOL can stop that swap. Raising the limit might let it complete at a lower output, so it trades a lower chance of failure for a worse possible fill.
Uniswap’s developer documentation describes tolerance as the price movement a swap will accept before it fails. It is separate from network gas and bridge costs: increasing it does not lower either cost or improve liquidity. If your route repeatedly fails, check whether the source swap or destination swap is the problem before changing the tolerance.
If you regularly move one asset across chains and want a different asset at the destination, a crypto relay bridge can handle the bridge and swap in one flow. A relay bridge is relevant when you want that combined route; the same minimum-output risk still depends on the swap and its execution conditions.
What should you do after a failure?
First, check the transaction status and identify which leg failed. A source-chain swap that reverts may leave the bridge transfer unstarted, while a destination swap can fail after assets have already crossed; what happens next depends on the route’s recovery rules.
Do not submit the full transfer again while the first route is still pending. Once it reaches a final status, check whether the funds were returned, delivered as the bridge asset, or need a route-specific recovery action. Then refresh the quote, compare the minimum output and route delay, and retry with a tolerance that matches the token’s liquidity and movement.
Does a higher tolerance make the swap cheaper?
No. It only permits a wider gap between the quoted output and the minimum you accept. The swap can still execute at the original price, but a higher limit allows a worse price if the market moves. It does not reduce bridge fees, network gas, or the price impact caused by a large trade.
Can a bridge transfer succeed while the swap fails?
Yes, on routes that bridge first and swap on the destination chain, the transfer can arrive even if the later swap cannot meet its minimum output. The route’s recovery rules determine whether you receive the bridged asset or can retry the swap. Check the final status before starting another transfer.
For frequent cross-chain swaps, treat tolerance as a price limit for a specific swap leg, then check what happened before you retry.