A payment flow needs 6 sequential steps with conditional branching, per-step retries, and visibility into which step failed. SQS or Step Functions?
A.Six chained SQS queues with Lambda consumers
Works but you hand-build state tracking, branching, and failure visibility — the orchestrator's job.
B.Step Functions state machine
Correct — managed orchestration is exactly what Step Functions is for.
C.A single large Lambda handling all steps
A monolith Lambda loses per-step retry granularity and hits timeout limits for long flows.
D.SNS fan-out to six Lambdas
SNS fan-out is parallel notification, not ordered workflow.
Why this answer
Step Functions models multi-step workflows natively: sequential/parallel/choice states, built-in retry with backoff, and a visual execution history per run. Chained SQS queues can do it but rebuild orchestration, retries, and observability by hand.
Correct answer: B · Last reviewed 2026-11-01
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