DVA-C02 Development with AWS Services Practice Question
A developer is building a RESTful API using Amazon API Gateway. The API experiences high traffic spikes, and many requests are for the same data (e.g., a product catalog). The developer wants to reduce the load on the backend Lambda functions and improve response times for repeated requests. Which feature should the developer enable?
⚠ Common exam trap
A common mix-up: candidates confuse API Gateway caching with CloudFront caching, thinking that CloudFront alone reduces backend load, but CloudFront caches at the edge and still forwards cache misses to API Gateway, which then invokes Lambda; only API Gateway caching directly reduces Lambda invocations for repeated requests.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable API Gateway caching and set a TTL.
API Gateway caching stores responses from backend Lambda functions for a configurable time-to-live (TTL). When a request for the same data (e.g., a product catalog) arrives within the TTL period, API Gateway serves the cached response directly, reducing the number of invocations to the Lambda function and improving response latency. This directly addresses the need to reduce load on the backend and improve response times for repeated requests.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Enable API Gateway caching and set a TTL.
Why this is correct
Enabling API Gateway caching directly addresses the problem by storing responses for a specified Time-To-Live (TTL). When subsequent identical requests arrive within the TTL, API Gateway serves the response from its managed cache, completely bypassing the backend Lambda function. This significantly reduces the load on the Lambda function, lowers invocation costs, and improves API response times for repeated requests.
- ✗
Use CloudFront with the API Gateway as an origin.
Why it's wrong here
Using CloudFront as a content delivery network (CDN) caches responses at edge locations, but the question requires reducing load on backend Lambda functions specifically for repeated API requests. CloudFront caches HTTP responses, not the underlying compute invocations; each cache miss still triggers a full Lambda execution. This option is tempting because CloudFront is commonly used to accelerate static content delivery and reduce origin load for cacheable responses, and it would be correct if the goal were to serve static assets or reduce latency for geographically distributed users rather than to cache API responses at the API Gateway layer itself.
- ✗
Enable throttling on the API Gateway usage plan.
Why it's wrong here
Enabling throttling on an API Gateway usage plan limits the rate at which clients can invoke API methods to protect the backend from being overwhelmed. While it prevents excessive load, it does not cache responses or improve the response time for repeated, valid requests. Instead, it rejects requests that exceed the defined rate limits, which is distinct from serving cached data to reduce backend invocations.
- ✗
Use a DynamoDB Accelerator (DAX) cluster for the backend database.
Why it's wrong here
Using a DynamoDB Accelerator (DAX) cluster caches read requests for DynamoDB tables, significantly improving read performance for the database layer. However, DAX operates at the database level and does not prevent the backend Lambda function from being invoked in the first place. The Lambda function would still execute for each API request, even if it subsequently retrieves data from DAX, thus not directly reducing the load on the Lambda compute itself.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
Go deeper
Related to this question
About these practice questions
Courseiva writes every DVA-C02 question from scratch — 724 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DVA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DVA-C02 exam.