- A
Enable API Gateway caching on the stage and configure the client ID header as a cache key parameter. Set a cache TTL of 5 minutes.
API Gateway caching uses cache key parameters to index responses. By including the client ID header in the cache key, different clients get separate cached responses. The TTL controls how long the response is cached.
- B
Configure a usage plan with a quota and throttle settings to limit requests per client ID.
Why wrong: Usage plans limit the number of requests but do not cache responses. They would still invoke the Lambda function for each request, just limiting the rate.
- C
Use request validation to reject requests that have the same client ID within 5 minutes.
Why wrong: Request validation checks the structure of the request but cannot detect duplicate payloads or cache responses. It is not designed for this purpose.
- D
Reduce the Lambda function's batch size to 1 and implement caching logic inside the function using an external cache like ElastiCache.
Why wrong: While this could work, it requires custom caching logic and adds complexity. The question asks for an API Gateway feature; the correct answer uses a built-in API Gateway capability.
DVA-C02 Development with AWS Services Practice Question
This DVA-C02 practice question tests your understanding of development with aws services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: aPI Gateway caching reduces backend load and improves latency.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer is building a REST API using Amazon API Gateway and AWS Lambda. The API receives a large number of requests with duplicate payloads from the same client within a short time window. To reduce Lambda invocations and improve performance, the developer wants to return the previously computed response for identical requests based on a unique client ID in the header. How can the developer achieve this using API Gateway features?
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 on the stage and configure the client ID header as a cache key parameter. Set a cache TTL of 5 minutes.
Option A is correct because API Gateway caching allows you to store responses for a configurable TTL and use the client ID header as a cache key parameter. This means that when a request with the same client ID arrives within the TTL window, API Gateway returns the cached response directly without invoking the Lambda function, reducing invocations and improving performance.
Key principle: API Gateway caching reduces backend load and improves latency.
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 on the stage and configure the client ID header as a cache key parameter. Set a cache TTL of 5 minutes.
Why this is correct
API Gateway caching uses cache key parameters to index responses. By including the client ID header in the cache key, different clients get separate cached responses. The TTL controls how long the response is cached.
Related concept
API Gateway caching reduces backend load and improves latency.
- ✗
Configure a usage plan with a quota and throttle settings to limit requests per client ID.
Why it's wrong here
Usage plans limit the number of requests but do not cache responses. They would still invoke the Lambda function for each request, just limiting the rate.
- ✗
Use request validation to reject requests that have the same client ID within 5 minutes.
Why it's wrong here
Request validation checks the structure of the request but cannot detect duplicate payloads or cache responses. It is not designed for this purpose.
- ✗
Reduce the Lambda function's batch size to 1 and implement caching logic inside the function using an external cache like ElastiCache.
Why it's wrong here
While this could work, it requires custom caching logic and adds complexity. The question asks for an API Gateway feature; the correct answer uses a built-in API Gateway capability.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse API Gateway caching (which returns cached responses for identical cache keys) with usage plans or throttling (which only limit request rates) or with Lambda-level caching (which still incurs invocation costs).
Detailed technical explanation
How to think about this question
API Gateway caching works by using a configurable cache key, which can include headers, query strings, or stage variables. When a request matches an existing cache key, API Gateway serves the cached response from its internal cache (typically backed by a dedicated cache cluster) without routing to the integration, thus reducing latency and cost. The TTL (Time-To-Live) controls how long the cached response is considered valid; setting it to 5 minutes ensures that duplicate requests within that window are served from cache, but after expiration the next request triggers a fresh Lambda invocation.
KKey Concepts to Remember
- API Gateway caching reduces backend load and improves latency.
- Cache keys determine if a request is a cache hit or miss.
- Headers like client ID can be included in the cache key for client-specific caching.
- Time-To-Live (TTL) defines how long responses are stored in the cache.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
API Gateway caching reduces backend load and improves latency.
Real-world example
How this comes up in practice
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
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FAQ
Questions learners often ask
What does this DVA-C02 question test?
Development with AWS Services — This question tests Development with AWS Services — API Gateway caching reduces backend load and improves latency..
What is the correct answer to this question?
The correct answer is: Enable API Gateway caching on the stage and configure the client ID header as a cache key parameter. Set a cache TTL of 5 minutes. — Option A is correct because API Gateway caching allows you to store responses for a configurable TTL and use the client ID header as a cache key parameter. This means that when a request with the same client ID arrives within the TTL window, API Gateway returns the cached response directly without invoking the Lambda function, reducing invocations and improving performance.
What should I do if I get this DVA-C02 question wrong?
Review aPI Gateway caching reduces backend load and improves latency., then practise related DVA-C02 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
API Gateway caching reduces backend load and improves latency.
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Last reviewed: Jun 11, 2026
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.
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