A queue carries financial transactions that must be processed exactly once and strictly in order. Which queue type should be selected?
A.Amazon SQS standard queue
Standard queues are at-least-once and best-effort ordering.
B.Amazon SQS FIFO queue with message deduplication
Correct. FIFO guarantees ordering and exactly-once processing.
C.An SNS topic
SNS is publish/subscribe fan-out, not an ordered queue.
D.Amazon EventBridge scheduler
EventBridge Scheduler triggers events on schedules; it is not a transaction queue.
Why this answer
SQS FIFO queues preserve message order and provide exactly-once processing via content-based or explicit deduplication IDs. Standard queues offer at-least-once delivery with best-effort ordering — not acceptable for strict ordering.
Correct answer: B · Last reviewed 2026-10-25
Official AWS references
Practice this interactively
Answer without seeing the solution first in the Decoupling & Messaging practice session.
Practice Decoupling & Messaging