Where the Value Goes in a Cross-Chain Swap

Across Protocol says a user deposits tokens on one chain and a relayer can deliver the requested asset on another, minus fees. The value is divided among the recipient, liquidity providers, relayer and network costs; the exact split depends on the route and the swap design.

A bridge transfer moves value between chains, while a cross-chain swap also changes the asset received. The linked Biswap explainer on cross-chain swaps and transfers covers that distinction in more detail. In practice, a service may arrange a source-chain trade, a cross-chain transfer, and a destination-chain trade, or have a relayer fill the destination order directly.

Who receives the fees in a cross-chain swap?

Across Protocol’s fee documentation says the difference between a user’s deposit and destination output can compensate liquidity providers and relayers. Liquidity providers earn for supplying capital and taking rebalancing risk; relayers are paid for fronting destination-chain funds and covering execution costs.

There may also be a trading fee in the swap itself, plus gas paid to execute transactions on one or both chains. The route can combine these costs in its quoted output, so the useful comparison is the amount that should arrive, not a headline fee in isolation.

Why can the received amount change?

Uniswap’s white paper describes how a trade through automated market maker pools depends on the available token reserves. A larger order relative to pool liquidity can move the price more; this price impact, alongside fees, reduces the output. A cross-chain quote can also change while the source transaction is pending or the destination trade is being filled.

Check these parts of the quote before signing:

• Output amount: the destination token and minimum amount the transaction allows.
• Fees: trading, liquidity-provider, relayer and network charges, where shown.
• Route: which chains and token conversions the service will use.
• Slippage setting: how far the received amount may move before execution fails or proceeds.

What happens to the tokens between chains?

Chainlink’s CCIP documentation describes several token-handling models. In lock-and-mint, tokens are held on the source chain and a corresponding token is minted on the destination; in burn-and-mint, tokens are destroyed on the source and issued on the destination. In a relayer model such as Across describes, the relayer may send destination funds first and receive reimbursement later.

These approaches put value in different places while a transfer completes: escrow, destination supply, or a relayer’s working capital. For most users, compare the final quoted output and route before approving, then follow the transaction status on both chains. Whether a particular swap will settle at the quoted amount remains unconfirmed until execution completes.