A finance department uses an internal REST API that handles about 3,000 requests a day, almost all during office hours, and each request finishes in under 300 ms. A few staff also use it in the evenings, so it must answer at any time of day. The API runs on two always-on Amazon EC2 instances behind an Application Load Balancer. Which change will reduce cost the MOST while keeping the API available at all times?
Choose one answer.
Show the answer and explanation
Answer: A
Explanation
At about 3,000 short requests a day, the API is idle almost all the time, so the biggest saving comes from not paying for idle capacity at all. API Gateway and Lambda are billed per request and per unit of compute used, with no minimum fees, and they still answer in the evening. Every other option keeps a load balancer and at least one server or task billed around the clock, or loses evening availability.