Question 465 of 981
AZ-900 Describe cloud concepts Practice Question
A startup wants to quickly deploy a web application without worrying about server maintenance. They only want to focus on writing code and deploying it. Which cloud service model best fits this requirement?
⚠ Common exam trap
Many exam-takers confuse PaaS with IaaS because both allow code deployment, but IaaS still requires the customer to manage the OS and middleware, which violates the 'no server maintenance' requirement.
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
✓
B) Platform as a Service (PaaS)
Platform as a Service (PaaS) provides a managed hosting environment where the cloud provider handles the underlying infrastructure (servers, storage, networking, OS patches) while the customer focuses solely on deploying and managing their own code and data. This directly matches the startup's requirement to avoid server maintenance and concentrate on writing and deploying code.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A) Infrastructure as a Service (IaaS)
Why it's wrong here
IaaS provides virtualized hardware — VMs, storage, and networking — which you must provision, secure, patch, and maintain. Running a web app on IaaS means you handle the OS, web server, runtime, and scaling yourself, so you are still worried about servers.
When this WOULD be correct
A company needs to migrate an on-premises workload to the cloud with full control over the OS, applications, and networking, and is willing to manage the underlying infrastructure (e.g., patching, scaling).
- ✓
B) Platform as a Service (PaaS)
Why this is correct
PaaS offers a managed hosting environment that abstracts the underlying OS, runtime, and scaling, so the developer focuses solely on application code and data. It includes built-in deployment, patching, and load-balancing, making it ideal for rapidly deploying web apps without server administration.
- ✗
C) Software as a Service (SaaS)
Why it's wrong here
SaaS delivers complete, ready-to-use software applications over the internet, licensed per user, where you configure but do not code or deploy. It does not offer a development platform to host your custom web application; you use the provider's product.
When this WOULD be correct
A question like: 'A company wants to use a customer relationship management (CRM) system without developing or maintaining any software. Which service model should they choose?' would make SaaS correct.
- ✗
D) Functions as a Service (FaaS)
Why it's wrong here
FaaS (e.g., Azure Functions) executes discrete, event-driven code snippets in response to triggers, with automatic scaling per invocation. It is not designed for long-running, stateful web applications with persistent sessions; you would need orchestration and additional services to build a full web app.
When this WOULD be correct
A question asking for a serverless compute model to run code in response to events (e.g., processing uploaded images or handling API requests) without managing servers, where the code is stateless and short-lived, would make FaaS the correct answer.
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 AZ-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓B) Platform as a Service (PaaS)Correct answer▾
Why this is correct
PaaS offers a managed hosting environment that abstracts the underlying OS, runtime, and scaling, so the developer focuses solely on application code and data. It includes built-in deployment, patching, and load-balancing, making it ideal for rapidly deploying web apps without server administration.
✗A) Infrastructure as a Service (IaaS)Wrong answer — click to see why▾
Why this is wrong here
IaaS provides virtualized servers and storage, but the startup would still need to manage the operating system, runtime, and middleware, which contradicts their desire to avoid server maintenance and focus solely on code.
★ When this WOULD be the correct answer
A company needs to migrate an on-premises workload to the cloud with full control over the OS, applications, and networking, and is willing to manage the underlying infrastructure (e.g., patching, scaling).
Why candidates choose this
Candidates may confuse IaaS with PaaS, thinking that any cloud service that allows deploying code is IaaS, or they may overestimate the level of abstraction IaaS provides.
✗C) Software as a Service (SaaS)Wrong answer — click to see why▾
Why this is wrong here
SaaS provides fully managed software applications, but the startup wants to deploy their own web application, not use an existing one. SaaS would not allow them to write and deploy custom code.
★ When this WOULD be the correct answer
A question like: 'A company wants to use a customer relationship management (CRM) system without developing or maintaining any software. Which service model should they choose?' would make SaaS correct.
Why candidates choose this
Candidates may confuse SaaS with PaaS because both are 'as a service' models, or they might think SaaS includes deployment capabilities, overlooking that SaaS delivers ready-to-use applications rather than a platform for custom code.
✗D) Functions as a Service (FaaS)Wrong answer — click to see why▾
Why this is wrong here
FaaS (Functions as a Service) is event-driven and executes individual functions in response to triggers, not designed for deploying a full web application without managing server infrastructure. The startup wants to deploy a web application, which typically requires a runtime environment and orchestration that PaaS provides, not just function execution.
★ When this WOULD be the correct answer
A question asking for a serverless compute model to run code in response to events (e.g., processing uploaded images or handling API requests) without managing servers, where the code is stateless and short-lived, would make FaaS the correct answer.
Why candidates choose this
Candidates may confuse FaaS with PaaS because both are serverless, but FaaS is more granular and event-driven, leading them to think it fits any 'no server maintenance' scenario, overlooking that web applications need a platform, not just functions.
Analysis generated from the official AZ-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Last reviewed: Jun 11, 2026
This AZ-900 practice question is part of Courseiva's free Microsoft 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 AZ-900 exam.
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