Fees & trade costs

Keep a reproducible record of a swap-cost comparison

Record the quote inputs, fee boundaries and transaction evidence needed for someone else to reproduce a swap-cost comparison.

A reproducible comparison needs more than a screenshot of the receiving amount. Preserve enough information to identify the requested trade, the state observed and the cost boundaries used. Another reader should be able to redo the arithmetic without guessing which charges were included.

A compact evidence record

GroupRecord
TradeNetwork, token contracts, direction, exact input or output, quantity
QuoteObservation time, quote amount, route if disclosed, expiry and receiving/spending bounds
CostsEach charge's asset, amount, recipient, inclusion status and estimate or actual designation
ValuationReference prices, timestamps and comparison currency
OutcomeSubmitted transaction, receipt, actual recipient balance change and failed attempts

Keep quoted and realized records separate

A hypothetical ledger might record 1,000 input, 997 quoted output and 0.80 of estimated separate costs. After execution, it might record 996.5 actual output and 0.70 actual separate costs. Retaining both versions makes the 0.40 deterioration in net value visible. Replacing the quote fields with receipt values destroys that comparison.

Ethereum's transaction lifecycle distinguishes a submitted operation from one included in a block. A quote without an executed transaction is still useful evidence, but it should not be labeled a tested fill.

State what cannot be reproduced

A later quote cannot recreate a missing historical quote. A transaction receipt cannot prove that an unexecuted alternative would have filled. Record these limits explicitly rather than filling missing fields with a current estimate.

For publication, remove unrelated wallet information from the displayed record while retaining the necessary arithmetic inputs. The audit goal is to substantiate the particular cost claim, not to publish an entire wallet history. A small, complete dataset is more useful than many unexplained screenshots.

Sources & verification (1)

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  1. Transactions

    Transaction lifecycle and receipt interpretation.

    https://ethereum.org/developers/docs/transactions/

Continue reading

Reconcile a quote, a receipt and wallet balance changes Does refreshing a quote prove that routing improved? How fee rounding changes very small swap calculations