DVA-C02 Development with AWS Services Practice Question
A developer is building a chat application using WebSockets. The application runs on multiple EC2 instances and needs to broadcast messages to all connected clients. Which AWS service can handle the WebSocket connections and route messages?
⚠ Common exam trap
It's easy for candidates to confuse Application Load Balancer's WebSocket support (which only proxies connections to a single target) with the need for a managed service that can broadcast to multiple clients, leading them to choose ALB over API Gateway.
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
✓
Amazon API Gateway WebSocket API
Amazon API Gateway WebSocket API is the correct choice because it natively manages WebSocket connections, maintains persistent bidirectional communication, and can broadcast messages to all connected clients using callback URLs. It handles connection lifecycle (connect, disconnect, default) and integrates with AWS Lambda or other backends to route messages efficiently.
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 SQS with long polling
Why it's wrong here
Amazon SQS is a message queuing service designed for asynchronous communication between decoupled application components, not for establishing or maintaining persistent, bidirectional WebSocket connections. While long polling can be used to retrieve messages from a queue, it represents a pull-based model for discrete messages, fundamentally different from the real-time, push-based protocol required for interactive chat applications.
- ✗
Application Load Balancer with WebSocket support
Why it's wrong here
An Application Load Balancer (ALB) can indeed route WebSocket traffic to backend targets and maintain persistent connections, which is a necessary capability for WebSocket-based applications. However, an ALB's core function is load distribution and routing; it does not inherently provide the server-side logic, state management, or broadcasting mechanisms required to send messages to multiple connected clients in a chat application.
- ✗
Amazon CloudFront with WebSocket support
Why it's wrong here
Amazon CloudFront is a Content Delivery Network (CDN) primarily optimized for caching and delivering static and dynamic content globally with low latency, and it can proxy WebSocket connections to improve performance. Nevertheless, CloudFront operates as an edge service and does not offer the backend capabilities or stateful logic necessary to manage WebSocket connection lifecycles or broadcast messages to all active clients in a chat application.
- ✓
Amazon API Gateway WebSocket API
Why this is correct
Amazon API Gateway WebSocket API is purpose-built for managing persistent, bidirectional communication channels required by real-time applications like chat. It natively handles WebSocket connection management, including connection establishment and termination, and provides robust mechanisms to send messages to specific clients or broadcast messages to all connected clients, often integrating with backend services like AWS Lambda for message processing.
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 |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.