Three costs in one swap
The network fee — gas — is paid to the validators of the chain, in that chain’s own coin. It does not depend on how much you swap: it depends on how busy the chain is and what the transaction does. A swap with an approval in front of it costs more than one without. This is the cost people forget when a $30 trade on a congested chain loses money.
The liquidity provider fee is inside the price you are quoted. Every pool charges the people who supply it — typically a fraction of a percent — and it is already subtracted from what you receive. It never appears as a line item, which is exactly why it is worth knowing it exists.
The platform fee is what the interface charges for assembling the trade. On FBT Swap it is 0.70% of the input amount, on every supported network, and it is shown on the screen before the wallet is asked to sign anything.
Why the number you were quoted is not the number you get
Two forces move the quote between the moment you see it and the moment the transaction is mined. Price impact is the effect of your own trade on the pool: in a deep pool a small trade moves the price almost not at all, and in a shallow pool even a modest trade moves it against you. Slippage is everything else moving — other people’s trades landing first.
A swap interface handles this with a minimum-received value. If the trade cannot fill at or above that floor, the transaction reverts instead of executing at a bad price. You pay the gas for the attempt and keep your tokens. That is the honest behaviour, but it is also why "the swap failed" and "you were charged" are not a contradiction.
What the 0.70% does and does not pay for
It pays for the interface: routing across the pools on the network you chose, the quote you read, the transaction your wallet signs. It is taken in the input token on the same chain, and it is the only part of the transaction that goes to us.
It does not cover gas, it does not cap price impact, and it does not buy reversibility. Nobody can reverse an on-chain trade — not the interface, not the pool, not the validators. A swap you signed is a swap that happened.
The pre-signature checklist
Before approving, confirm five things: the network matches the token you actually hold; the price impact is a number you are willing to accept; the minimum received is above your own floor, not just the default; the fee line names the amount and the chain; and the deadline is short enough that a stuck transaction cannot execute at a stale price later.
If any of those is missing from the screen, the correct move is not to sign and check somewhere else. A quote that hides one of its own costs is not a cheaper quote, it is an incomplete one.
Where to look in the app
On every swap the app shows the route, the platform fee, the price impact and the minimum received before your wallet is opened. After signing, the transaction hash is on the explorer of that chain for anyone to verify — including you.
If a fee line ever disagrees with what left your wallet, that is a bug worth reporting, not something to explain away.