Cursor-based pagination in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this cursor-based pagination response?

Given this REST API response for a cursor-based pagination request, what is the value of next_cursor?

Rest API

{
  "data": ["item21", "item22", "item23"],
  "next_cursor": "MjQ=",
  "has_more": true
}

A "item23"

B "MjQ="

C "has_more"

D "data"

💡 Hint

Look for the field that represents the cursor for the next page.

The next_cursor field contains the encoded cursor string to fetch the next page. Here it is "MjQ=".

🧠 Conceptual

intermediate

Why use cursor-based pagination instead of offset-based pagination?

Which of the following is the main advantage of cursor-based pagination over offset-based pagination?

A It avoids skipping or duplicating items when data changes during pagination.

B It allows jumping directly to any page number without sequential access.

C It requires less server memory to store all pages at once.

D It always returns the total number of items in the dataset.

💡 Hint

Think about what happens if new items are added or removed while paginating.

Cursor-based pagination uses a stable cursor to continue from the last item, preventing skipping or duplication when data changes. Offset-based pagination can miss or repeat items if the dataset changes.

🔧 Debug

advanced

Identify the error in this cursor-based pagination API response

What error will this API response cause when used for cursor-based pagination?

Rest API

{
  "data": ["item10", "item11"],
  "next_cursor": null,
  "has_more": true
}

A The <code>next_cursor</code> should be an integer, not null.

B The <code>has_more</code> field must be false if <code>next_cursor</code> is present.

C The <code>next_cursor</code> is null but <code>has_more</code> is true, causing inconsistent pagination.

D The <code>data</code> array is empty, so no items to paginate.

💡 Hint

Check if the cursor and has_more fields agree on whether more data exists.

If has_more is true, there should be a valid next_cursor to continue pagination. Null cursor with has_more true is inconsistent and will cause errors.

📝 Syntax

advanced

Which option correctly encodes the cursor in a REST API response?

Choose the correct JSON snippet that encodes the cursor as a base64 string for the next page.

A { "next_cursor": 'aXRlbTQ1' }

B { "next_cursor": base64_encode("item45") }

C { "next_cursor": b"aXRlbTQ1" }

D { "next_cursor": "aXRlbTQ1" }

💡 Hint

Remember JSON strings must use double quotes and no function calls inside JSON.

Option D correctly uses a base64 encoded string in double quotes. Option D is invalid JSON with a function call. Option D uses Python bytes syntax, invalid in JSON. Option D uses single quotes, invalid in JSON.

🚀 Application

expert

How many items will be returned after two pages with this cursor-based pagination setup?

An API returns 3 items per page. The dataset has 7 items total. After fetching two pages using cursor-based pagination, how many unique items have been retrieved?

A 6

B 7

C 3

D None, cursor-based pagination does not guarantee unique items

💡 Hint

Calculate items per page times pages fetched, but consider total items available.

Each page returns 3 items. Two pages return 6 items total. Since dataset has 7 items, 6 unique items are retrieved after two pages.