Malformed JSON bodies keep reaching your Lambda and crashing it. Which API Gateway feature rejects bad requests before they hit the backend?
A.Usage plans with throttling
Usage plans control rate/quota — not payload shape.
B.Request validation with a JSON schema model
Correct — schema validation at the gateway layer.
C.A WAF rule on the API
WAF inspects attack patterns, not JSON schema conformance.
D.Lambda authorizer checking the body
An authorizer runs a Lambda before the real one — it authenticates, and invoking Lambdas to validate bodies wastes invocations.
Why this answer
API Gateway request validation checks the body against a JSON schema model (and required params/headers) at the edge — invalid requests return 400 without invoking your function, saving cost and noise.
Correct answer: B · Last reviewed 2026-11-01
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