4.24Retry + idempotency belong together

This is crucial.

Never say:

“We retry failures three times.”

without thinking:

“What happens if the first attempt actually succeeded but the response was lost?”

Example:

Mule → Salesforce

Salesforce creates Account

Salesforce → Mule response lost

Mule sees timeout

Then:

retry CREATE

creates another Account.

That's why:

retry strategy
+
idempotency

must be designed together.

Great interview sentence:

“I don't consider retries independently from idempotency, because a timeout doesn't prove the downstream operation wasn't committed.”

That's senior-level integration thinking.