Quick Answer
Amazon Cognito is the correct choice because it is a fully managed identity service designed specifically for web and mobile applications that need to manage user identities and provide single sign-on. It handles user sign-up, sign-in, and access control natively, and supports SSO through federation with social identity providers like Google or Facebook, as well as enterprise identity providers via SAML 2.0 or OIDC. On the AWS Certified Developer Associate DVA-C02 exam, this question tests your understanding of identity management in a decoupled architecture—specifically, that Cognito integrates seamlessly with an Application Load Balancer for authentication, whereas services like IAM are for internal AWS users, not external app users. A common trap is choosing IAM or Directory Service, but remember: IAM is for AWS API access, not for your web app’s customers. Memory tip: “Cognito for customers, IAM for admins.”
This DVA-C02 practice question tests your understanding of security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 designing a web application that will run on EC2 instances behind an Application Load Balancer. The application needs to authenticate users. Which service should the developer use to manage user identities and provide single sign-on?
AWS IAM
Why wrong: For AWS services, not app users.
Amazon Cognito
User pools for app authentication.
AWS Directory Service
Why wrong: For Microsoft AD.
AWS Security Token Service (STS)
Why wrong: For temporary AWS credentials.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Amazon Cognito
Amazon Cognito is the correct choice because it is a fully managed identity service designed for web and mobile applications. It provides user sign-up, sign-in, and access control, and supports single sign-on (SSO) through federation with social identity providers (e.g., Google, Facebook) and enterprise identity providers via SAML 2.0 or OIDC. This makes it ideal for authenticating users in an application running behind an Application Load Balancer.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
AWS IAM
Why it's wrong here
For AWS services, not app users.
Amazon Cognito
Why this is correct
User pools for app authentication.
Related concept
Read the scenario before looking for a memorised answer.
AWS Directory Service
Why it's wrong here
For Microsoft AD.
AWS Security Token Service (STS)
Why it's wrong here
For temporary AWS credentials.
Common exam traps
The trap here is confusing AWS IAM (for AWS resource access) with a customer-facing identity service, leading candidates to choose IAM for user authentication instead of Cognito.
Detailed technical explanation
Amazon Cognito user pools act as an identity broker, issuing JSON Web Tokens (JWTs) after successful authentication, which can be validated by the application or the ALB using its built-in authentication rule. The ALB can directly authenticate users against a Cognito user pool, offloading the authentication flow from the application code and simplifying SSO implementation. A real-world scenario is a multi-tenant SaaS application where Cognito handles user registration, password recovery, and MFA, while the ALB enforces access control before requests reach the EC2 instances.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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.
What to study next
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FAQ
Security — This question tests Security — Read the scenario before looking for a memorised answer..
The correct answer is: Amazon Cognito — Amazon Cognito is the correct choice because it is a fully managed identity service designed for web and mobile applications. It provides user sign-up, sign-in, and access control, and supports single sign-on (SSO) through federation with social identity providers (e.g., Google, Facebook) and enterprise identity providers via SAML 2.0 or OIDC. This makes it ideal for authenticating users in an application running behind an Application Load Balancer.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 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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