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Aporeon interview preparation

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Message Queues & Events

Reliability

At-least-once delivery, idempotency, retries, dead letters, locks, ordering, lag, and operations.

8 drillsPractice one at a timeOrdered pathConcept questionArchitecture scenarioDebugging scenario

Recommended start

At-least-once Delivery

Explains why message handlers must tolerate duplicate delivery and how idempotency protects side effects.

Hard~9 minStep 1 of 8

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1At-least-once DeliveryRecommended startExplains why message handlers must tolerate duplicate delivery and how idempotency protects side effects.Concept questionHard~9 min.NETAmazon SQSAzure Service BusPractice 2

Practice order

8 drillsOne at a time

1At-least-once DeliveryUp next / Hard / ~9 min
2Inbox PatternHard / ~12 min
3Retry PolicyMedium / ~7 min
4

Inbox PatternMakes consumer-side deduplication atomic with the business change while supporting concurrent delivery, retention, replay, and failed processing.Architecture scenarioHard~12 min.NETAmazon SQSAzure Service Bus

Practice

3Retry PolicyExplains retry strategy for transient failures and poison-message handling for permanent failures.Concept questionMedium~7 min.NETAmazon SQSAzure Service BusPractice

4DLQ RecoveryExplains how to inspect, fix, replay, skip, or archive dead-letter messages without repeating bad side effects.Debugging scenarioHard~12 min.NETAmazon SQSAzure Service BusPractice

5Message LocksKeeps long-running queue work safe when message ownership expires, renewal fails, settlement is uncertain, or another worker receives the same job.Concept questionHard~9 min.NETAmazon SQSAzure Service BusPractice

6Message OrderingPreserves order only within the business key that requires it, while handling hot keys, gaps, stale events, replay, and poison messages explicitly.Architecture scenarioHard~12 min.NETAmazon SQSAzure Service BusPractice

7Queue LagExplains operational signals for queue-backed systems and how to respond when consumers fall behind.Debugging scenarioMedium~10 min.NETAmazon SQSAzure Service BusPractice

8Distributed workflow reconciliationRepairs a workflow when a remote operation may have succeeded but local state, messages, and callbacks disagree.Architecture scenarioHard~12 min.NETASP.NET CoreAzure Service BusPractice

DLQ Recovery

Hard / ~12 min

5Message LocksHard / ~9 min

6Message OrderingHard / ~12 min

7Queue LagMedium / ~10 min

8Distributed workflow reconciliationHard / ~12 min

Reliability - Message Queues & Events | Aporeon