easyMultiple ChoiceObjective-mapped
CAS-004 Practice Question: A developer is creating a REST API that handles…
A developer is creating a REST API that handles sensitive data. Which HTTP method should be used for updates that are not idempotent?
⚠ Common exam trap
The key pitfall is that many candidates mistakenly believe PUT can be used for any update operation. However, PUT is idempotent, meaning it must result in the same state regardless of how many times it is applied. For non-idempotent updates (e.g., appending data), POST is the appropriate method because it can create side effects that change state differently with each request.
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
✓
POST
POST is correct because it is not idempotent, meaning multiple identical requests can result in different outcomes (e.g., creating a new resource each time). For updates that are not idempotent, POST is the appropriate HTTP method as it allows side effects such as appending data or triggering a process, unlike PUT which is idempotent and replaces the entire resource.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DELETE
Why it's wrong here
DELETE is idempotent; deleting a resource multiple times yields the same outcome.
- ✗
GET
Why it's wrong here
GET is a safe, idempotent method used for retrieval, not updates.
- ✗
PUT
Why it's wrong here
PUT is idempotent; repeated calls produce the same result.
- ✓
POST
Why this is correct
POST is non-idempotent and suitable for operations that create or update resources with potentially different results on each call.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.