A bridge swap can deliver less than you send because it trades one asset for another while moving between networks. The final amount depends on the exchange rate, available trading funds, and costs along the route.
That differs from how integrators choose Manta bridge, which weighs the service itself; here, the key is what your route is expected to deliver. Manta bridge is relevant when you want to move and swap assets across networks in one flow.
Why can the amount change?
The amount changes because a bridge swap combines a transfer with a trade. A route may first exchange your asset on the starting network, move value across networks, then exchange it again for the asset you want.
A quoted rate is an estimate of what the trade should return at that moment. The quote can change before the trade completes because prices move and other trades use the same available funds.
Liquidity means the amount of an asset available for trading. A large trade against a small pool of available funds can move the price more than a small trade against a deep pool. This effect is called price impact.
For the transfer itself, mantabridge.org gives you a way to move and swap assets across chains in one flow. The amount shown for the destination asset is the useful figure to compare with other routes.
Where does the difference go?
Some value goes to costs required to process each part of the route. These may include network transaction fees, a service fee, and the trading cost built into the exchange rate.
- Network fee: paid to process a transaction on a blockchain. On Ethereum, for example, this fee is paid in ETH.
- Service fee: a charge for arranging or carrying out the transfer and trade, if the route applies one.
- Trading cost: the effect of the exchange rate and available liquidity on how much the trade returns.
- Destination fee: a possible cost for processing the receiving transaction on the destination network.
These costs do not always appear as separate deductions. A route may include some costs in the quoted destination amount, while a network fee may be charged separately. Check the quote’s description so you know which amount is expected to arrive and which fees you still need to pay.
How can you compare two quotes?
Compare the amount you expect to receive, using the same starting amount and destination asset. A route with a lower displayed fee can still deliver less if its exchange rate is worse or its available liquidity is thinner.
For example, say you start with 1 ETH and compare two routes to the same destination token. Route A estimates 2,000 tokens after its included costs; Route B estimates 1,970. If Route A also requires a separate destination fee worth 15 tokens, its practical result is about 1,985, still 15 tokens above Route B.
Before sending, check the asset and network named for both ends of the transfer. Also check whether the estimate includes fees and whether you must hold a separate token to pay a network fee.
What does “minimum received” mean?
Slippage is the difference between the quoted price and the price when a trade actually executes. A minimum received amount sets the lowest output you accept. If the trade would return less, the swap may stop instead of completing at that worse price.
For example, if a quote estimates 2,000 tokens and the minimum is 1,980, a 1,990-token result can proceed, but a 1,970-token result should not. A wider gap allows more price movement; a narrower gap gives stronger protection but can make a route fail more often when prices move quickly.
Choose a different route if its net destination amount is clearly better and you understand its separate costs. If prices are moving sharply, liquidity is low, or the minimum is far below the estimate, wait or accept a smaller trade. The right choice changes when a better quote no longer covers the extra cost and risk.