Plural vs singular resource names in Rest API - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Choosing resource names for REST API endpoints

Which of the following is the best practice for naming a REST API endpoint that returns a list of users?

A /user

B /users

C /userlist

D /getUsers

💡 Hint

Think about how REST APIs usually represent collections.

REST APIs typically use plural nouns for resource collections. So, /users is the standard way to represent a list of user resources.

❓ Predict Output

intermediate

Output of REST API endpoint for singular resource

Given a REST API endpoint /users/123 that returns the user with ID 123, what is the expected resource name in the URL?

A /users/123

B /user/123

C /userses/123

D /userlist/123

💡 Hint

Remember that the collection is plural, and the ID identifies a single resource inside it.

The resource name remains plural for the collection, and the ID specifies the singular resource. So /users/123 is correct.

❓ Predict Output

advanced

Identify the correct REST API endpoint for creating a new book

Which endpoint should be used to create a new book resource in a REST API?

A POST /book

B GET /books/create

C POST /books

D PUT /books/new

💡 Hint

Creating a new resource usually uses POST on the collection endpoint.

POST requests to the plural resource endpoint /books are the standard way to create new resources in REST APIs.

🧠 Conceptual

advanced

Why avoid singular resource names for collections?

Why is it generally discouraged to use singular resource names like /user to represent a collection in REST APIs?

A Because singular names are harder to type

B Because singular names are reserved keywords in HTTP

C Because singular names require special headers

D Because singular names confuse clients about whether the endpoint returns one or many resources

💡 Hint

Think about clarity and expectations for API users.

Using singular names for collections can confuse clients about whether the endpoint returns a single resource or a list, reducing API clarity.

🚀 Application

expert

Determine the number of items returned by the endpoint

A REST API endpoint /products returns a JSON array of product objects. If the endpoint returns the following JSON:

[{"id":1,"name":"Pen"},{"id":2,"name":"Notebook"},{"id":3,"name":"Eraser"}]

How many product items does this endpoint return?

A 3

B 2

C 1

D 4

💡 Hint

Count the objects inside the JSON array.

The JSON array contains three objects, so the endpoint returns 3 product items.

Practice

1. Which naming style is recommended for an API endpoint that returns a list of users?
/user or /users?

easy

A. /users because it is singular and more precise.

B. /user because it is shorter and simpler.

C. /user because it is singular and more precise.

D. /users because it represents multiple users.

Solution

1. Step 1: Understand resource naming for collections

   API endpoints returning multiple items should use plural names to clearly indicate a list.

2. Step 2: Apply naming to the example

   Since the endpoint returns multiple users, /users is the correct plural form.

3. Final Answer:

   /users because it represents multiple users. -> Option D

4. Quick Check:

   Plural for lists = /users [OK]

Hint: Use plural names for endpoints returning lists [OK]

Common Mistakes:

• Using singular for list endpoints
• Confusing singular and plural forms
• Choosing shorter names over clarity

2. Which of the following is the correct endpoint to access a single product by its ID?

easy

A. /products/123

B. /product/123

C. /products

D. /product

Solution

1. Step 1: Identify singular vs plural for single item access

   When accessing a single item by ID, use the plural form of the resource name followed by the ID.

2. Step 2: Match the correct endpoint format

   The endpoint /products/123 uses plural products and includes the ID, which is the common RESTful convention.

3. Final Answer:

   /products/123 -> Option A

4. Quick Check:

   Single item access = plural + ID [OK]

Hint: Use plural resource name when accessing one item by ID [OK]

Common Mistakes:

• Using singular resource name for single item
• Omitting the ID when accessing a single item
• Mixing singular/plural inconsistently

3. Given the following API endpoints, which one correctly retrieves a list of orders?

GET /order
GET /orders
GET /order/456
GET /orders/456

medium

A. GET /order

B. GET /orders/456

C. GET /orders

D. GET /order/456

Solution

1. Step 1: Identify endpoints returning lists

   Endpoints returning lists should use plural resource names without an ID.

2. Step 2: Analyze each option

   GET /orders uses plural and no ID, so it returns the list of orders. Others either use singular or include an ID, indicating single item access.

3. Final Answer:

   GET /orders -> Option C

4. Quick Check:

   List retrieval = plural resource without ID [OK]

Hint: Plural + no ID means list retrieval [OK]

Common Mistakes:

• Choosing singular endpoint for list
• Confusing ID presence with list retrieval
• Ignoring plural vs singular rules

4. You have an API endpoint defined as GET /users/ to get a list of users and GET /user/{id} to get a single user. A developer mistakenly uses GET /user/ to get all users. What is the likely problem?

medium

A. The endpoint /user/ is incorrect for list retrieval and may cause a 404 error.

B. The endpoint /user/ will return a list of users anyway.

C. The endpoint /user/ will return a single user without ID.

D. The endpoint /user/ will automatically redirect to /users/.

Solution

1. Step 1: Understand endpoint naming conventions

   List retrieval requires plural resource name, so /users/ is correct for all users.

2. Step 2: Analyze the incorrect usage

   /user/ is singular and without an ID, so it likely does not exist or returns an error like 404.

3. Final Answer:

   The endpoint /user/ is incorrect for list retrieval and may cause a 404 error. -> Option A

4. Quick Check:

   Singular without ID ≠ list endpoint [OK]

Hint: Singular without ID usually causes errors for list requests [OK]

Common Mistakes:

• Using singular endpoint for list retrieval
• Assuming singular endpoint returns list
• Expecting automatic redirects between endpoints

5. You are designing an API for a library system. Which of the following endpoint designs correctly follows the plural vs singular resource naming best practices for retrieving a single book and all books?

hard

A. GET /book for all books and GET /books/{id} for a single book

B. GET /books for all books and GET /book/{id} for a single book

C. GET /books/{id} for all books and GET /book for a single book

D. GET /book/{id} for all books and GET /books for a single book

Solution

1. Step 1: Recall naming rules for collections and single items

   Use plural resource names for collections (all books) and singular for single items by ID.

2. Step 2: Match options to rules

   GET /books correctly retrieves all books (plural). GET /book/{id} correctly retrieves a single book (singular with ID).

3. Final Answer:

   GET /books for all books and GET /book/{id} for a single book -> Option B

4. Quick Check:

   Plural for list, singular + ID for single [OK]

Hint: Plural for lists, singular + ID for single items [OK]

Common Mistakes:

• Swapping singular and plural for list vs single
• Using singular without ID for list
• Using plural with ID for single item