What swap records do non-custodial platforms keep and when do they delete them

07 September 2026

Non-custodial platforms typically keep the on-chain transaction record forever, and they delete nothing themselves because they never held it in the first place. The swap itself is written into the blockchain’s public ledger, which is permanent, while any off-chain data the platform’s interface generated - like order books, quote logs, or session cookies - is usually discarded within days or weeks unless a law requires otherwise.

The distinction matters more than most people expect. When you use a non-custodial platform, the smart contract executes the trade. That contract’s inputs and outputs are recorded on-chain. No employee of the platform can erase that. No server crash removes it. The blockchain is not a database with a delete button. Your swap’s hash, the amounts, the wallet addresses, and the timestamp are all there, indefinitely, readable by anyone.

What the platform does control is the front-end layer. That includes the temporary data your browser exchanged with their servers while you were clicking through the interface. Some platforms log IP addresses, device fingerprints, or the exact route their aggregator chose for your order. Others keep nothing more than a short-lived session token. Retention varies wildly because there is no single rule. A platform’s privacy policy might state a 30-day log purge. Another might retain analytics data for a year. A third might keep nothing at all beyond what the blockchain already has.

When does deletion actually happen? Three scenarios cover most cases. First, the platform’s own policy deletes logs on a schedule - commonly 30, 90, or 180 days. Second, a legal demand, such as a court order or a tax authority request, can force retention beyond that schedule. In that case, the platform freezes relevant logs until the matter resolves. Third, the platform itself shuts down. If its servers go dark, whatever was stored there is gone, unless a backup survived. That is why the on-chain record is the only reliable copy.

You might ask why a platform would keep even a short-lived log if the chain has everything. The answer is practical. The chain records the settlement, not the journey. If you swapped token A for token B, the chain shows that. It does not show which liquidity pool the platform routed you through, what price quote you saw first, or whether you clicked “confirm” twice. Those details live in the platform’s logs, and they are exactly the kind of thing a tax office might later question. But they are also exactly what the platform has little reason to preserve beyond its own legal minimum.

A common misconception is that non-custodial platforms are obligated to keep swap records for you. They are not. You are the custodian of your own paperwork. The platform’s role is to execute the contract, not to archive your financial history. So when you complete a swap, you should assume the interface data is temporary. The blockchain data is permanent. Anything else is a courtesy, not a guarantee.

One more layer: some platforms use third-party indexers or analytics services. Those services may retain their own copies of transaction data, often longer than the platform itself. But you cannot rely on that either. Indexers can change their retention policies, or they can disappear. The only constant is the chain itself.

If you need to reconstruct a swap later, the on-chain hash is your starting point. That hash, plus a screenshot of the confirmation screen, plus the wallet address you used, is usually enough to satisfy an auditor. The platform’s logs are a bonus, not a foundation. And if the platform vanishes, the chain still remembers.

For the practical side of what to save before you close that confirmation window, the sibling page on screenshot details covers the exact fields that matter. That page sits under the same hub as this one, and it is the natural next read if you want to know what a tax office will actually ask to see.

Back to arbitrum