Question

A developer maintains a customer-facing Lambda function invoked synchronously through API Gateway. During periodic traffic spikes, users report intermittent latency of several seconds on the first requests after idle periods, while steady-state requests are fast. The function must respond within a strict latency SLA even for the initial requests of a spike. Which approach best addresses this issue?

Accepted Answer

Configure provisioned concurrency on the function alias and use Application Auto Scaling to adjust it ahead of expected traffic.

Answer

Increase the function timeout so the slow initial requests have time to complete.

Answer

Set a reserved concurrency limit on the function to guarantee capacity during spikes.

Answer

Switch the API Gateway integration from synchronous to asynchronous (event) invocation.