Link relations in responses in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this REST API response with link relations?

Given the following JSON response from a REST API, what is the value of the "next" link relation URL?

Rest API

{
  "data": ["item1", "item2"],
  "links": {
    "self": "https://api.example.com/items?page=1",
    "next": "https://api.example.com/items?page=2",
    "prev": null
  }
}

A "https://api.example.com/items?page=2"

B "https://api.example.com/items?page=1"

C null

D "https://api.example.com/items?page=3"

💡 Hint

Look for the "next" key inside the "links" object.

The "next" link relation provides the URL for the next page of items, which is "https://api.example.com/items?page=2".

🧠 Conceptual

intermediate

What is the purpose of link relations in REST API responses?

Why do REST APIs include link relations like "self", "next", and "prev" in their responses?

A To provide URLs that describe how to navigate or interact with related resources.

B To store user credentials for authentication.

C To compress the response data for faster transfer.

D To define the data schema of the response.

💡 Hint

Think about how clients can use these links to move between pages or related data.

Link relations help clients discover related resources or actions by providing URLs with semantic names like "next" or "self".

🔧 Debug

advanced

Why does this REST API response cause a client error when following the "next" link?

Consider this JSON response snippet: { "links": { "self": "https://api.example.com/items?page=1", "next": "htp://api.example.com/items?page=2" } } Why will a client fail to fetch the "next" page?

A The "self" link is missing a trailing slash.

B The "next" URL has a typo in the scheme: "htp" instead of "http".

C The "next" link is missing the query parameter "page".

D The JSON response is missing a "prev" link.

💡 Hint

Check the URL scheme spelling carefully.

The "next" link URL uses "htp" which is not a valid scheme, causing clients to fail when trying to fetch it.

📝 Syntax

advanced

Which option correctly represents a HAL-style link relation in JSON?

HAL (Hypertext Application Language) uses a specific JSON format for links. Which of the following is the correct HAL link representation for a "self" link?

A "links": { "self": "https://api.example.com/items/1" }

B "links": { "self": { "url": "https://api.example.com/items/1" } }

C "_links": { "self": "https://api.example.com/items/1" }

D "_links": { "self": { "href": "https://api.example.com/items/1" } }

💡 Hint

HAL requires the "href" key inside the link object.

HAL defines links inside an "_links" object with each link as an object containing an "href" property.

🚀 Application

expert

How many link relations are present in this paginated API response?

Given this JSON response: { "data": ["a", "b"], "links": { "self": "https://api.example.com/data?page=3", "first": "https://api.example.com/data?page=1", "prev": "https://api.example.com/data?page=2", "next": "https://api.example.com/data?page=4", "last": "https://api.example.com/data?page=10" } } How many distinct link relations are included in the "links" object?

A 3

B 4

C 5

D 6

💡 Hint

Count all keys inside the "links" object.

The "links" object contains "self", "first", "prev", "next", and "last" — a total of 5 link relations.