Question 148 of 1,040
Design Secure ArchitectureshardMultiple SelectObjective-mapped

SAA-C03 Design Secure Architectures Practice Question

This SAA-C03 practice question tests your understanding of design secure architectures. 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. 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 startup has an HTTP API with highly unpredictable traffic from mobile devices. Each request performs lightweight validation, writes an event record, and triggers downstream notifications. The current EC2 fleet stays mostly idle, and the team wants to reduce infrastructure management and pay only for usage. Which two changes best fit the requirement? Select two.

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "best"

    Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

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

Place Amazon API Gateway in front of AWS Lambda functions for request handling.

Option A is correct because Amazon API Gateway can directly invoke AWS Lambda functions, eliminating the need to manage EC2 instances. This serverless architecture scales automatically with unpredictable traffic, and you pay only for the requests and compute time consumed, which aligns with the startup's goal of reducing idle costs and infrastructure management.

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.

  • Place Amazon API Gateway in front of AWS Lambda functions for request handling.

    Why this is correct

    API Gateway plus Lambda fits spiky request traffic well because it removes server management and charges are based on actual use.

    Clue confirmation

    The clue word "best" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Keep the EC2 fleet and add more instances so the idle cost is less noticeable.

    Why it's wrong here

    Adding more always-on servers increases idle spend and directly contradicts the goal of paying only for usage.

    When this WOULD be correct

    For a workload with steady, predictable traffic where the team needs to ensure consistent performance and has already optimized instance utilization, adding more instances can handle growth without rearchitecting.

  • Use Amazon SQS to buffer notification work and decouple it from the request path.

    Why this is correct

    SQS absorbs bursts and separates the user-facing request from downstream processing, improving cost efficiency and operational resilience.

    Clue confirmation

    The clue word "best" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Move the API to an Application Load Balancer only, without changing compute.

    Why it's wrong here

    An ALB can distribute traffic, but it does not remove the need to manage EC2 instances or eliminate idle capacity.

    When this WOULD be correct

    A question where the workload has steady traffic, requires session persistence, or needs advanced routing (e.g., path-based or host-based routing) and the team is already using EC2 with no desire to change compute model.

  • Store runtime secrets in user data on each instance.

    Why it's wrong here

    This does not address variable traffic or cost optimization, and it creates a poor secret-handling pattern.

    When this WOULD be correct

    In a scenario where a legacy application requires secrets to be passed at boot time and the environment is fully controlled with immutable instances that are replaced frequently, using encrypted user data with instance metadata service (IMDSv2) could be acceptable for temporary secrets.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SAA-C03 exam frequently reuses these exact scenarios with slightly different constraints.

Place Amazon API Gateway in front of AWS Lambda functions for request handling.Correct answer

Why this is correct

API Gateway plus Lambda fits spiky request traffic well because it removes server management and charges are based on actual use.

Keep the EC2 fleet and add more instances so the idle cost is less noticeable.Wrong answer — click to see why

Why this is wrong here

Keeping the EC2 fleet and adding more instances increases infrastructure management and idle costs, contradicting the goal to reduce management and pay only for usage.

★ When this WOULD be the correct answer

For a workload with steady, predictable traffic where the team needs to ensure consistent performance and has already optimized instance utilization, adding more instances can handle growth without rearchitecting.

Why candidates choose this

Candidates may think that adding more instances is a simple scaling solution, overlooking that it increases idle costs and management overhead, which the question explicitly wants to avoid.

Move the API to an Application Load Balancer only, without changing compute.Wrong answer — click to see why

Why this is wrong here

Moving the API to an Application Load Balancer only, without changing compute, still requires managing EC2 instances that remain mostly idle, failing to reduce infrastructure management and pay-per-usage requirements.

★ When this WOULD be the correct answer

A question where the workload has steady traffic, requires session persistence, or needs advanced routing (e.g., path-based or host-based routing) and the team is already using EC2 with no desire to change compute model.

Why candidates choose this

Candidates may think an ALB alone reduces management because it handles traffic distribution, but overlook that the underlying EC2 fleet still incurs idle costs and management overhead.

Store runtime secrets in user data on each instance.Wrong answer — click to see why

Why this is wrong here

Storing runtime secrets in user data on each EC2 instance is insecure and not scalable; secrets should be managed with AWS Secrets Manager or Parameter Store, not embedded in instance metadata.

★ When this WOULD be the correct answer

In a scenario where a legacy application requires secrets to be passed at boot time and the environment is fully controlled with immutable instances that are replaced frequently, using encrypted user data with instance metadata service (IMDSv2) could be acceptable for temporary secrets.

Why candidates choose this

Candidates may think user data is a convenient way to pass configuration to instances, but they overlook security best practices and the fact that user data is accessible to anyone with instance metadata access.

Analysis generated from the official SAA-C03blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates might think adding more EC2 instances (Option B) or using an ALB (Option D) solves the idle cost problem, but these options still require managing servers and incur idle costs, whereas serverless options (A and C) eliminate idle costs entirely.

Detailed technical explanation

How to think about this question

API Gateway supports throttling and request validation at the edge, reducing Lambda invocations for malformed requests. SQS decouples the notification work from the request path, allowing Lambda to process events asynchronously and retry on failure, which is ideal for downstream notifications that can tolerate latency. This pattern (API Gateway + Lambda + SQS) is a common serverless architecture for handling spiky traffic with minimal cost.

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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.

Quick reference

Cloud Service Model Comparison

ModelYou ManageProvider ManagesExamples
IaaSOS, runtime, apps, dataHardware, hypervisor, networkingEC2, Azure VMs, GCP Compute Engine
PaaSApps and dataOS, runtime, middleware, hardwareElastic Beanstalk, Azure App Service
SaaSData and settings onlyEverything elseMicrosoft 365, Salesforce, Workday
FaaS / ServerlessFunction code onlyInfra, scaling, runtimeLambda, Azure Functions, Cloud Run
CaaSContainers and appsKubernetes, OS, hardwareEKS, AKS, GKE

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this SAA-C03 question test?

Design Secure Architectures — This question tests Design Secure Architectures — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Place Amazon API Gateway in front of AWS Lambda functions for request handling. — Option A is correct because Amazon API Gateway can directly invoke AWS Lambda functions, eliminating the need to manage EC2 instances. This serverless architecture scales automatically with unpredictable traffic, and you pay only for the requests and compute time consumed, which aligns with the startup's goal of reducing idle costs and infrastructure management.

What should I do if I get this SAA-C03 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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This SAA-C03 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 SAA-C03 exam.