- A
Use Amazon CloudFront to proxy the API and add CORS headers.
Why wrong: CloudFront is not necessary for CORS.
- B
Enable CORS in the API Gateway settings and configure the required headers.
API Gateway can be configured to return CORS headers.
- C
Nothing; API Gateway automatically handles CORS.
Why wrong: CORS must be explicitly enabled.
- D
Add CORS headers in the Lambda function code.
Why wrong: API Gateway handles CORS; Lambda responses do not include CORS headers unless proxied.
Question 504 of 1,616
Enable CORS in API Gateway
This DVA-C02 practice question tests your understanding of development with aws services. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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 using Amazon API Gateway to create a REST API. The API must support CORS (Cross-Origin Resource Sharing) to allow requests from a web application hosted on a different domain. What must the developer do to enable CORS?
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 CORS in the API Gateway settings and configure the required headers.
Option B is correct because enabling CORS in API Gateway requires explicit configuration: you must enable CORS on the API Gateway resource, which automatically generates an OPTIONS method and adds the necessary CORS headers (Access-Control-Allow-Origin, Access-Control-Allow-Methods, Access-Control-Allow-Headers) to responses. This is done through the API Gateway console or API configuration, not by the backend Lambda function or CloudFront.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use Amazon CloudFront to proxy the API and add CORS headers.
Why it's wrong here
CloudFront is not necessary for CORS.
- ✓
Enable CORS in the API Gateway settings and configure the required headers.
Why this is correct
API Gateway can be configured to return CORS headers.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Nothing; API Gateway automatically handles CORS.
Why it's wrong here
CORS must be explicitly enabled.
- ✗
Add CORS headers in the Lambda function code.
Why it's wrong here
API Gateway handles CORS; Lambda responses do not include CORS headers unless proxied.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume API Gateway automatically handles CORS (Option C) or that adding headers only in the Lambda function is sufficient (Option D), forgetting that the browser's preflight OPTIONS request must be handled by API Gateway itself.
Detailed technical explanation
How to think about this question
CORS is enforced by the browser, not the server; the browser sends a preflight OPTIONS request to check if the cross-origin request is allowed. API Gateway's CORS configuration automatically creates a mock OPTIONS response with the required headers, but if you need dynamic CORS headers (e.g., variable origins), you must implement the OPTIONS method manually in the backend. A common real-world scenario is when using custom authorizers or Lambda integrations that need to return CORS headers for both preflight and actual requests.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
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 |
What to study next
Got this wrong? Here's your next step.
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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 — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Enable CORS in the API Gateway settings and configure the required headers. — Option B is correct because enabling CORS in API Gateway requires explicit configuration: you must enable CORS on the API Gateway resource, which automatically generates an OPTIONS method and adds the necessary CORS headers (Access-Control-Allow-Origin, Access-Control-Allow-Methods, Access-Control-Allow-Headers) to responses. This is done through the API Gateway console or API configuration, not by the backend Lambda function or CloudFront.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 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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