DVA-C02 Development with AWS Services Practice Question
This DVA-C02 practice question tests your understanding of development with aws services. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: vTL templates transform request/response data in API Gateway.. 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 wants to transform the request data before sending it to the backend Lambda function. The transformation includes mapping query string parameters to a JSON body. Which API Gateway feature should be used?
Velocity Template Language (VTL) mapping templates
Mapping templates in API Gateway use VTL to transform request data, such as converting query string parameters into a JSON body before passing to Lambda.
B
Lambda authorizer
Why wrong: Lambda authorizers are used to validate and authorize API requests, not to transform request data.
C
Request validator
Why wrong: Request validators check the request against a JSON schema but do not perform any data transformation.
D
CORS configuration
Why wrong: CORS configuration controls whether cross-origin requests are allowed, but does not transform request data.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Velocity Template Language (VTL) mapping templates
Option A is correct because API Gateway uses Velocity Template Language (VTL) mapping templates to transform incoming request data, such as mapping query string parameters into a JSON body before passing it to the backend Lambda function. This feature allows you to define a template that extracts values from the request's query string parameters (e.g., `$input.params('paramName')`) and constructs a new JSON payload, enabling seamless integration with Lambda without modifying the client request.
Key principle: VTL templates transform request/response data in API Gateway.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Velocity Template Language (VTL) mapping templates
Why this is correct
Mapping templates in API Gateway use VTL to transform request data, such as converting query string parameters into a JSON body before passing to Lambda.
Related concept
VTL templates transform request/response data in API Gateway.
✗
Lambda authorizer
Why it's wrong here
Lambda authorizers are used to validate and authorize API requests, not to transform request data.
✗
Request validator
Why it's wrong here
Request validators check the request against a JSON schema but do not perform any data transformation.
✗
CORS configuration
Why it's wrong here
CORS configuration controls whether cross-origin requests are allowed, but does not transform request data.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse request validation (Option C) with data transformation, assuming that validating the request structure also implies the ability to reshape the data, but validation only checks for presence and format, not mapping or transformation.
Detailed technical explanation
How to think about this question
Under the hood, API Gateway's VTL mapping templates use Apache Velocity syntax to access the `$input` variable, which provides methods like `$input.params()` for query string parameters, `$input.path()` for path parameters, and `$input.body` for the request body. The template is evaluated at runtime, and the resulting JSON is passed as the event to the Lambda function. A real-world scenario is when a legacy client sends query parameters but the Lambda expects a structured JSON payload; the mapping template can also handle conditional logic or default values, such as `#if($input.params('page') == '') 1 #else $input.params('page') #end`.
KKey Concepts to Remember
VTL templates transform request/response data in API Gateway.
They use Velocity Template Language for scripting transformations.
VTL can map query strings, headers, and body to new payloads.
Mapping templates are configured per method integration request/response.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
VTL templates transform request/response data in API Gateway.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. VTL templates transform request/response data in API Gateway. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Review vTL templates transform request/response data in API Gateway., then practise related DVA-C02 questions on the same topic to reinforce the concept.
Development with AWS Services — This question tests Development with AWS Services — VTL templates transform request/response data in API Gateway..
What is the correct answer to this question?
The correct answer is: Velocity Template Language (VTL) mapping templates — Option A is correct because API Gateway uses Velocity Template Language (VTL) mapping templates to transform incoming request data, such as mapping query string parameters into a JSON body before passing it to the backend Lambda function. This feature allows you to define a template that extracts values from the request's query string parameters (e.g., `$input.params('paramName')`) and constructs a new JSON payload, enabling seamless integration with Lambda without modifying the client request.
What should I do if I get this DVA-C02 question wrong?
Review vTL templates transform request/response data in API Gateway., then practise related DVA-C02 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
VTL templates transform request/response data in API Gateway.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.