Separate 1inch Classic quote and swap transaction requests

A successful 1inch Classic quote does not establish that the selected wallet can execute the trade. Pricing and transaction construction answer different questions, so give them separate application states.

The Classic quick start describes quote, allowance and swap construction as distinct operations. Its documented v6.1 integration requires the transaction path to account for the wallet and its prerequisites.

Keep discovery lightweight

Use a quote to compare the requested pair and amount. Associate it with the chain, trade direction and request generation. The form may show a browsing estimate before the account is ready, provided it does not advertise that estimate as an executable transaction.

When moving to review, check the selected account, chain, balance and permission. Request the swap payload for the actual execution context using the current endpoint schema. Do not convert a quote response into a transaction by adding a hardcoded router.

Freeze the reviewed intent

Keep the built transaction bound to its input amount, recipient and slippage setting. If any of those change, discard the executable state and rebuild. A delayed response must not overwrite a newer form generation.

Inspect the returned destination, data and native value, then simulate the same transaction context where supported. Preserve the difference between provider construction success and an independently observed successful simulation.

Explain the failure stage

If pricing works but construction fails, show that the application found an estimate but could not prepare execution. This is more accurate than claiming there is no market for the pair.

Record the endpoint version and sanitized request context so engineering can distinguish a missing prerequisite from a schema error. Avoid automatic slippage increases or validation bypasses; those alter either the user's trade constraint or the evidence available before submission.