Plural vs singular resource names in Rest API - Quick Revision & Key Differences

Recall & Review

beginner

Why do REST APIs usually use plural resource names?

Plural resource names represent collections of items, making it clear that the endpoint deals with multiple resources, like /users for many users.

beginner

What does a singular resource name usually represent in REST APIs?

A singular resource name often represents a single item or entity, typically used in the URL when accessing or modifying one specific resource, like /users/123.

beginner

Which is the recommended way to name a resource collection endpoint: /book or /books?

The recommended way is /books because it clearly indicates a collection of book resources.

beginner

How would you name an endpoint to get a single user by ID?

Use the plural resource name followed by the ID, like /users/123, to indicate you want one user from the users collection.

intermediate

Is it okay to mix singular and plural resource names in the same API?

It is best to be consistent and use plural names for collections and singular only when referring to a single resource by ID. Mixing can confuse users and developers.

Which URL is best for accessing all products in a REST API?

A /products

B /product

C /getProducts

D /allproducts

Using the plural noun /products clearly indicates a collection of product resources.

How should you name the endpoint to update a single order with ID 45?

A /order/45

B /orders/update/45

C /orders/45

D /updateOrder/45

Use the plural resource name with the ID: /orders/45 to target one order.

Why avoid using singular resource names for collection endpoints?

A They confuse the meaning of the endpoint

B They require more server memory

C They are slower to load

D They are harder to type

Singular names suggest a single item, so using them for collections can confuse users about what the endpoint returns.

Which is the best practice for REST API resource naming?

A Use uppercase letters in URLs

B Use singular for all endpoints

C Use verbs in resource names

D Use plural for collections and singular for single items

Plural names for collections and singular for single items keep the API clear and consistent.

What does the URL /users/789 typically represent?

A A collection of users

B A single user with ID 789

C A search for users

D An error page

The plural users followed by an ID usually means one user resource.

Explain why REST APIs prefer plural resource names for collections and how singular names are used.

Think about how you talk about groups vs. one item in real life.

Describe the potential confusion if singular resource names are used for collections in REST APIs.

Imagine asking for 'book' but getting many books instead.

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