How do I match a swap I made on Arbitrum to a deposit on another chain

07 September 2026

You match a swap on Arbitrum to a deposit on another chain by locating the cross-chain bridge transaction that moved your funds out of Arbitrum, then finding the corresponding inbound transaction on the destination chain. The bridge contract emits events on both chains that are linked by a unique identifier - usually a sequence number or a hash of the bridge request.

Why this works

When you swap tokens on Arbitrum and then see a deposit appear on, say, Ethereum or Base, the two events are not directly connected by a single transaction hash. The swap happens on Arbitrum. The deposit happens on the destination chain. The bridge - the mechanism that locks tokens on one side and mints or releases them on the other - creates the link. You need to find that bridge record.

Most bridges that handle cross-chain swaps from Arbitrum work the same way. You send tokens to a bridge contract on Arbitrum. That contract emits a Transfer or Deposit event with a unique nonce or request ID. The same nonce appears in the Mint or Withdraw event on the destination chain. Match the nonce, and you have matched the swap to the deposit.

Steps to find the match

1. Get the Arbitrum transaction hash of the swap. If you lost it, see the sibling page "How do I find a swap transaction hash on Arbitrum after I lost the link". You need that hash to start.

2. Open a block explorer for Arbitrum. Paste the transaction hash. Look at the internal transactions or the event logs. You are looking for a Transfer event to a contract address that is the bridge. The bridge address is often the same across chains for a given provider. The event log will contain a field called nonce, requestId, or sequenceNumber. Copy that value.

3. Switch to a block explorer for the destination chain. If you do not know which chain received the deposit, check the swap interface you used. Most swap interfaces show the destination chain in the transaction history. If you cannot find it, you may need to search multiple chains - this is why saving the swap confirmation screen matters. See "What details should I screenshot before I close a swap confirmation screen".

4. Search for the bridge contract on the destination chain. The bridge address is the same as on Arbitrum, but the contract is separate. Look for recent Mint or Withdraw events from that contract. Filter by the nonce you copied. If the bridge is a well-known provider, you can use its own explorer or dashboard to search by nonce directly.

5. Confirm the match. The destination transaction will show the same token, the same amount (minus any bridge fee), and the same nonce. The destination address is your wallet. The time difference between the Arbitrum transaction and the destination transaction is typically a few minutes, but can be longer if the bridge is congested.

Why you need this for tax records

A tax authority may ask why a deposit appeared on one chain when you claim you swapped on another. Without the matching bridge record, the deposit looks like an unexplained inbound transfer. That can trigger questions about income or gifts. The bridge record proves it was your own funds moving. The sibling page "Arbitrum swap receipts and tax records" explains what else you should keep alongside this match.

What can go wrong

• The bridge may use a different nonce format. Some bridges use a hash of the request, not a simple number. You still match it - the hash appears in both event logs.
• The swap may have been routed through multiple bridges. Example: Arbitrum to an intermediate chain, then to the final chain. You need to match each leg separately.
• The swap interface may have abstracted the bridge away. In that case, the transaction on Arbitrum might show a swap to a token that is then bridged automatically. The same nonce matching applies, but you may need to dig into the internal calls of the swap transaction.

Keep the Arbitrum transaction hash, the destination chain transaction hash, and the bridge nonce together. That is the minimal set of evidence that one swap became one deposit.

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