Why a cross-chain swap may need two fee currencies

A cross-chain swap may use one token to buy another and separate coins to pay network fees on each chain. That matters because the amount shown as your trade budget may not cover the cost of sending and completing it. Check what the quote takes from your wallet and what it subtracts from the amount you receive.

Why can a swap use two fee currencies?

A swap has at least two jobs: exchanging tokens and recording transactions on blockchains. The exchange may use a stablecoin or other token you chose. Network fees, often called gas, are paid in the chain’s own fee currency. A cross-chain route can involve a transaction on the starting chain and another on the destination chain.

Fees also depend on the route. A decentralized exchange may charge a trading fee from the pool, while a bridge or relayer may charge to move value between chains. Some routes include destination costs in the quote or take them from the output. For the separate question of how QuickSwap handles treasury transfers, see the linked explainer. Those transfer details are separate from the gas coins a trader needs in a wallet.

What should I check in the quote?

Read the quote as a breakdown of what you spend and what you should receive. A single “swap” button can hide several costs. Look for:

• The input token and the amount taken from your wallet.
• Network fees, and the currency and chain in which each is charged.
• Trading and bridge fees, if shown as separate line items.
• The minimum amount you will receive after price movement and fees.

That last figure matters because the displayed output can change before the transaction completes. Slippage is the difference between the expected price and the price at execution. A minimum output sets a floor; if the route cannot meet it, the swap may fail instead of delivering less.

How do I budget for both chains?

Keep enough of each chain’s fee currency available for the route. For example, if you start with a stablecoin on one network and want a different token on another, the stablecoin funds the trade. The starting network’s native coin may pay for the first transaction. The destination network may also need a fee coin, unless the route covers that cost or deducts it from the received amount.

Before confirming, check whether fees are taken upfront or from the output, and whether a failed attempt can still cost gas. If the quote does not explain the destination fee, check the route’s fee details before sending. The practical budget is the trade amount plus the fees the route actually asks you to pay, in the currencies it accepts.