Across bundles a bridge and swap to cut repeat fees

Across can combine a cross-chain transfer and a token swap in one route, so you may not need to make a separate swap transaction after your funds arrive. You choose the source and destination chains, the token to send and the token you want to receive. Across’s Swap API returns a quote and the transaction data to carry out that route. The bundle can reduce repeated network costs, but it does not make every fee disappear.

How does an Across bridge-and-swap route work?

The route starts with the tokens you hold on the origin chain and the tokens you want on the destination chain. Across’s API checks the chains and tokens, then builds a quote for the requested amount. Depending on the route, a swap can happen before the transfer, after it, or on both sides. The quote includes the expected output and fee details.

Next, you check whether your wallet needs to approve the input token. An approval lets the relevant contract use your tokens; it can require a separate transaction and gas. Once any required approval is in place, you submit the main transaction on the origin chain. A relayer uses its own funds to fill the transfer on the destination chain, then later claims repayment through Across’s settlement process.

The route can deliver a different token from the one you sent, rather than leaving you to bridge first and trade on arrival. For the basic bridge mechanics and the main Across bridge and swap types, see this guide to Across bridge and swap types. Across aggregates relayer fills into settlement bundles; that settlement step is separate from the user’s decision to bundle a swap into a transfer.

Which fees can bundling avoid?

Bundling can remove a separate wallet interaction and the network fee for an extra transaction, such as a swap you would otherwise make on the destination chain. Think of it as arranging a delivery to arrive already sorted: fewer steps for you, while the underlying service still has costs.

The route still uses liquidity, relayer capital and chain transactions. Across’s documentation says its transfer fees compensate liquidity providers and relayers; a swap can also have market impact, and the origin-chain transaction still uses gas. A destination action, such as depositing the received token into an app, may be included in the same route when supported, but that does not mean it has no execution cost.

So “fewer transactions” is a useful goal, not a guaranteed lower total cost. A combined quote can cost more than a simple bridge if its swap has poor liquidity or an unfavorable exchange rate. Compare what you will spend and receive against the separate steps before you confirm.

How should you read the quote?

Start by checking the route’s input and output tokens, networks and recipient. Then compare the amount you expect to receive with the amount you need. Across supports different trade types: with an exact-input quote, you set how much to send and the output depends on fees, slippage and exchange rates. With a minimum-output quote, you set the least you will accept and the required input is calculated for that target.

Before signing, look at the full quote rather than focusing on a single fee line. Check:

• Expected output: Does the destination token amount meet your need?
• Fee breakdown: What is charged for the transfer, swap and any app fee?
• Approval steps: Does the wallet need a separate approval transaction?
• Route details: Are the origin and destination chains and tokens correct?

The quote is specific to the route and market conditions when it is made, so refresh it before submitting if details change. Bundling makes the most practical sense when you already know the destination token you need and would otherwise perform another on-chain swap. If you only need to move the same token, a plain bridge route may be simpler. The right comparison is the final amount delivered and the transactions required, not the word “bundle” on its own.