DEX essentials

A swap quote is not a completed trade

Track the difference between a calculated offer, authorization, submission and a settled token exchange.

A quote describes a proposed exchange. Settlement changes balances under the rules of the executing contracts. Between the two, the user or another authorized participant must authorize and submit the required action, and the network must process it successfully.

Four events that interfaces can blur

EventWhat it establishesWhat it does not establish
Quote appearsAn estimated or offered exchangeThat balances have changed
Authorization is signedPermission under specified termsSuccessful settlement
Transaction is submittedAn execution request existsSuccessful inclusion
Settlement succeedsExecution has changed stateThat the original estimate was exact

Ethereum's transaction lifecycle separates broadcast and inclusion. Intent protocols add a different path: CoW's order flow places solver competition between the user's order and onchain settlement.

A quote can remain only a quote

Suppose an application estimates 250 B for 100 A. If you close the page without authorizing anything, the estimate does not reserve those tokens for you unless the service explicitly offers a reservation mechanism. Refreshing later can produce a different proposal.

A signed intent can also remain unfilled. It expresses permission to settle if its constraints are met; it is not itself proof that a matching execution exists or has occurred. A transaction hash similarly identifies a submission rather than proving success by its mere presence.

Use the correct record

When asking what you received, inspect the settled result. When asking what the application offered, retain the quote and its timestamp. When assessing authorization, inspect the signed terms. These are three different evidence sets.

This separation is especially useful when a front end displays an optimistic completion message before final network status arrives. The account state and successful settlement record determine whether the exchange happened. A quote screenshot is useful context, but it cannot substitute for that record.

Sources & verification (2)

Source-check date is recorded in the article details. URLs are provided for manual verification. Use Copy to keep this page open.

  1. Transactions | ethereum.org

    Transaction fields, native value versus calldata, inclusion and finality.

    https://ethereum.org/developers/docs/transactions/
  2. Flow of an order

    Intent submission, auction, solver execution and settlement lifecycle.

    https://docs.cow.fi/cow-protocol/concepts/how-it-works/flow-of-an-order

Continue reading

Swap simulation vs actual execution A route can be optimal for a snapshot and weaker at execution Swap settlement vs transaction confirmation