Can I prove I swapped tokens if the exchange site no longer exists

07 September 2026

Yes, you can still prove you swapped tokens even if the exchange site is gone - but only if you saved the right records at the time of the swap. If you did not save anything, the proof is likely unrecoverable.

The exchange site is just the front-end interface. The actual swap happens on a blockchain. That blockchain is a permanent ledger. If you have the transaction hash, the block number, and the wallet addresses involved, you can reconstruct the swap details from any block explorer. Those records do not depend on the exchange site being online.

What you need to have saved:

• The transaction hash (TXID) for each swap leg. This is the single most important piece of evidence. It is a unique identifier that lets anyone query the blockchain.
• The wallet addresses you used, both the sending and receiving addresses. If you used a smart contract, also note the contract address.
• The block number and approximate timestamp. The block explorer will show the exact time the block was confirmed.
• The token symbols and amounts. For Polygon, ERC-20 tokens, or any chain, the block explorer shows the exact transfer amounts and the token contract addresses. You can verify which token it was, even if the exchange site called it something else.
• If the swap involved a multi-step process (e.g., wrapping tokens, approving a contract, then swapping), you need the TXID for each step. A single swap may produce three or more blockchain transactions.

Why the exchange site disappearing does not erase your proof:

The exchange site is a convenience layer. It shows you a user-friendly confirmation screen. That screen is not the legal record. The legal record is the blockchain transaction. The transaction hash is a permanent pointer to that record. Even if the exchange site is deleted, the hash still works. Anyone with access to the block explorer (which is public and permanent) can verify the swap.

What you cannot prove without records:

• The exchange rate you were offered. The blockchain shows the net amounts you sent and received. It does not show the price quote the exchange site displayed. If you did not screenshot the confirmation screen showing the rate, you cannot prove the rate was fair or what you expected.
• The fees the exchange site charged. The blockchain shows network gas fees. It does not show any hidden markup the exchange site added to the spread. Without a screenshot of the fee breakdown, that information is gone.
• The identity of the counterparty. On a decentralized exchange, the counterparty is a smart contract, not a person. You cannot prove who you traded with beyond the contract address.
• Any promises or terms the exchange site made. If the site claimed it would refund failed swaps, or guaranteed a minimum output, those claims vanish with the site. A blockchain record does not capture those promises.

How to reconstruct proof if you have the hash:

Go to a block explorer for the relevant chain (e.g., Polygonscan for Polygon, Etherscan for Ethereum). Enter the transaction hash. The explorer will display the from address, to address, token amounts, block number, and timestamp. You can download or print that page as a PDF. That is your proof. It is timestamped by the blockchain, not by the exchange site.

What if you never saved the hash?

Then you cannot prove the swap. The blockchain is public, but without a starting point - a hash, a wallet address, or a block number - you cannot find the transaction. Searching by approximate date and amount is possible only if you know the exact wallet address you used. If you do not remember which wallet you used, the swap is effectively lost.

The hub page for this topic is "Which swap records to keep for tax time." That page explains exactly what to save before the exchange site disappears, so you never have to ask this question. If you are reading this after the fact, the hub page will tell you what to do differently next time.

Summary:

Keep the transaction hash. Save the wallet addresses. Take a screenshot of the confirmation screen, especially the rate and fees. The exchange site may vanish. The blockchain does not. Without your own records, you cannot prove the swap. With them, you can prove it forever.

Back to polygon