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Channels, Messaging and Real-World Integrations

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Lesson 4.1 · 60 minutes

Debug retries, duplicates, and delivery claims

Use event identity and durable decision records so retries are safe and delivery status means something precise.

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Channels, Messaging and Real-World Integrations

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Draft lesson: awaiting independent technical and publication review; do not use it as production configuration guidance.

Editorial review pendingon version support under review

Action boundary

Before you act

Expected result
Replaying one synthetic event creates no second external side effect and leaves an inspectable decision record.
Failure mode
A timeout is mistaken for no delivery and a retry repeats an external action.
Rollback
Stop retries, mark the event unresolved, and reconcile using the provider-specific delivery receipt.

Orient

“Sent” is too vague. Record whether an event was accepted, queued, attempted, acknowledged, or confirmed. Use the provider’s event identity where available; otherwise create an owned idempotency key before the side effect.

Perform

Define a decision record with event ID, verified sender, route version, approval ID, outbound intent, provider receipt reference, state, and timestamp. Replay the same synthetic event twice.

Check

The second run must find the first decision before delivery. A timeout remains unresolved until provider evidence says otherwise; do not call it a failure or success on a hunch.

Debug order

Trace event identity → endpoint verification → route decision → idempotency record → approval decision → outbound receipt. If identity or intended recipient is unproved, stop.

Continue

Use those records to make human approval explicit in Lesson 5.1.

Lesson checkpoint

Ready to move on?

Mark this lesson complete when you can apply its outcome without relying on the examples above.