The answer is Amazon API Gateway, the fully managed AWS service that serves as the front door for RESTful APIs connecting to backend Lambda functions and EC2 services. It is the correct choice because API Gateway natively provides built-in API key management, throttling with both rate limiting and burst limits, and usage plan enforcement—all essential for protecting backend resources from overload while controlling access. On the AWS Certified Cloud Practitioner CLF-C02 exam, this question tests your understanding of core API management features versus other services like Application Load Balancer or CloudFront, which lack integrated API key and usage plan controls. A common trap is confusing API Gateway with a simple load balancer, but remember that API Gateway is purpose-built for creating, securing, and monitoring APIs at scale. Memory tip: think of API Gateway as the "bouncer" that checks API keys, limits traffic with throttling, and enforces usage plans before letting requests reach your Lambda or EC2 backends.
CLF-C02 Cloud Technology and Services Practice Question
This CLF-C02 practice question tests your understanding of cloud technology and 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. 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 company wants to create RESTful APIs that serve as the front door to their backend Lambda functions and EC2 services. They need features including API key management, throttling to protect backends from overload, and usage plan enforcement. Which AWS service provides this?
Why wrong: CloudFront is a CDN for caching and delivering content. While it can be used with API Gateway, it is not itself an API management service with key management and throttling for backend APIs.
B
AWS Direct Connect
Why wrong: Direct Connect is a dedicated network connection service. It does not create or manage APIs.
C
Amazon API Gateway
API Gateway is the AWS service for creating, publishing, and managing APIs. It handles API key management, throttling to protect backend services, usage plans, and integrates natively with Lambda and EC2.
D
Amazon Route 53
Why wrong: Route 53 is a DNS service. While it routes traffic, it does not create APIs, manage API keys, or enforce throttling policies.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Amazon API Gateway
Amazon API Gateway is a fully managed service that makes it easy for developers to create, publish, maintain, monitor, and secure RESTful APIs at any scale. It directly provides built-in API key management, throttling (rate limiting and burst limits), and usage plan enforcement to protect backend services like Lambda functions and EC2 instances from overload. These features are core to API Gateway's functionality, making it the correct choice for acting as the front door to the described backend resources.
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.
✗
Amazon CloudFront
Why it's wrong here
CloudFront is a CDN for caching and delivering content. While it can be used with API Gateway, it is not itself an API management service with key management and throttling for backend APIs.
✗
AWS Direct Connect
Why it's wrong here
Direct Connect is a dedicated network connection service. It does not create or manage APIs.
✓
Amazon API Gateway
Why this is correct
API Gateway is the AWS service for creating, publishing, and managing APIs. It handles API key management, throttling to protect backend services, usage plans, and integrates natively with Lambda and EC2.
Related concept
Read the scenario before looking for a memorised answer.
✗
Amazon Route 53
Why it's wrong here
Route 53 is a DNS service. While it routes traffic, it does not create APIs, manage API keys, or enforce throttling policies.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Amazon CloudFront's edge caching and origin shielding capabilities with API management features, mistakenly thinking CloudFront can handle API key validation and throttling, when in fact CloudFront lacks native API key management and usage plan enforcement.
Detailed technical explanation
How to think about this question
Under the hood, API Gateway uses a tiered throttling model with account-level, stage-level, and method-level rate limits, where burst limits are enforced using a token bucket algorithm with a default bucket size of 5000 requests per second. Usage plans allow you to associate API keys with individual customers, setting per-key rate limits and quota limits (e.g., requests per day/week/month) that are enforced at the API Gateway edge. In a real-world scenario, a company might use API Gateway to expose a public REST API to third-party developers, where each developer gets a unique API key and is throttled to 1000 requests per hour to prevent a single user from overwhelming the backend Lambda functions.
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
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CLF-C02 question in full detail.
Cloud Technology and Services — This question tests Cloud Technology and Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Amazon API Gateway — Amazon API Gateway is a fully managed service that makes it easy for developers to create, publish, maintain, monitor, and secure RESTful APIs at any scale. It directly provides built-in API key management, throttling (rate limiting and burst limits), and usage plan enforcement to protect backend services like Lambda functions and EC2 instances from overload. These features are core to API Gateway's functionality, making it the correct choice for acting as the front door to the described backend resources.
What should I do if I get this CLF-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.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is building a serverless web application using AWS Lambda for compute. The application needs to expose RESTful API endpoints that allow users to perform CRUD operations on a database. The API must support authentication using API keys, throttle requests to prevent abuse, and validate incoming request payloads before they reach the Lambda functions. The company wants a fully managed service that handles these API management tasks and integrates directly with AWS Lambda. Which AWS service should the company use?
medium
A.Amazon CloudFront
✓ B.Amazon API Gateway
C.Application Load Balancer
D.AWS Step Functions
Why B: Amazon API Gateway is a fully managed service that handles RESTful API creation, authentication via API keys, request throttling to prevent abuse, and request payload validation before invoking AWS Lambda functions. It integrates natively with Lambda, making it the ideal choice for serverless web applications requiring CRUD operations with built-in API management.
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This CLF-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 CLF-C02 exam.
Question Discussion
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