A read-heavy REST API calls a Lambda that queries DynamoDB — most requests repeat the same lookups. Which API Gateway feature reduces backend load without code changes?
A.Usage plans
Usage plans throttle/quota clients, not backend calls.
B.API Gateway response caching with a TTL
Correct. Stage-level cache with TTL cuts repeat backend invocations.
C.Request validation
Validation rejects bad input earlier — it doesn't cache responses.
D.Stage variables
Stage variables parameterize config, not caching.
Why this answer
REST APIs support response caching per stage — responses are served from the cache for the TTL, skipping the backend entirely. (Note: the cheaper HTTP API type has no caching — an exam-worthy distinction.)
Correct answer: B · Last reviewed 2026-10-27
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