What information does a swap site need from you to route between two chains

05 September 2026

A swap site needs your destination address, the asset and amount you are sending, and the source chain's transaction hash once you broadcast the payment. That is the minimum set; anything else it asks for is either for refunds, for compliance, or because it is not really routing a swap.

The core job is simple. You give the site a destination address on the other chain. It watches the source chain for your incoming transaction. When it sees enough confirmations, it releases the corresponding asset on the destination chain. To do that, it must know three things: where you want the funds to go, what you are sending, and proof that you sent it.

The destination address. This is non-negotiable. The site cannot move value to a chain it cannot name a recipient on. The address must be valid for that specific network. Sending a Bitcoin address to an Ethereum route will fail, and the failure is not the site's fault. Some sites derive a fresh destination address for you; others let you paste your own. Either way, that address is the only thing that tells the site where the swap ends.

The source asset and amount. The site needs to know which token you are spending and how much. This is not just for accounting. The routing logic depends on it. A swap from USDC on one chain to USDC on another might use a direct liquidity pool. A swap from a less liquid token might require two hops. The site cannot pick a path without knowing the starting point and the size. The amount matters because fees and slippage are calculated from it. If you send more than you declared, the surplus is usually lost or returned, depending on the site's policy.

The source transaction hash. This is the proof of payment. The site does not trust you to say "I sent it." It watches the mempool or the chain state for a transaction that matches your swap parameters. The hash is how it finds that transaction. In practice, many sites let you paste the hash manually after you broadcast, because watching for it automatically is slower and more error-prone. The hash also lets the site confirm the exact amount and the fee you paid, which matters if you underpaid the network fee and the transaction is stuck.

Now, the things a site might ask for that are not strictly necessary.

A refund address on the destination chain. This is not part of routing. It is an insurance policy. If the swap fails after you send your funds - say the destination chain is congested or the liquidity pool dries up - the site needs somewhere to send your money back. The refund address is that somewhere. Sibling pages cover this in detail, but the short version is: if a site does not ask for one, it either keeps your funds on failure or sends them to an address it controls, which is a different risk.

Identity documents or KYC data. This has nothing to do with routing. If a site asks for a passport or a selfie, it is complying with laws in its jurisdiction, not enabling the swap. Some sites do this for large amounts. Some do it for all amounts. The routing works the same either way; the extra data is a legal filter, not a technical one.

An account or login. A site that requires an account before you can swap is collecting more than routing data. It may be keeping a record of your activity. That is not the same as being custodial - your coins are still not held in a site wallet - but it does mean the site knows who you are and what you did. That is a privacy trade-off, not a technical requirement.

What the site never needs is your private keys, your seed phrase, or a signature that spends more than the exact swap amount. If it asks for those, it is not routing a swap; it is trying to take your funds. A genuine non-custodial swap only needs enough information to watch the blockchain and issue a payment.

The practical rule is this: count the questions. The three essential ones - destination address, asset and amount, source transaction hash - are the whole technical apparatus. A refund address is a sensible fourth. Anything beyond that is administrative, and you should weigh whether the site's need for it matches your tolerance for sharing.

If you want to see how these pieces fit together in a real trade, the hub page on swapping crypto across chains walks through the order of operations. That page connects this one to the rest of the set, including what happens when timers expire and how you verify a provider is honestly non-custodial.

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