Cursor-based pagination in Rest API - Step-by-Step Execution

Concept Flow - Cursor-based pagination

Client requests first page

↓

Server returns data + cursor

↓

Client stores cursor

↓

Client requests next page with cursor

↓

Server returns next data + new cursor

↓

Repeat until no more data

↓

End

The client asks for data pages. The server sends data plus a cursor. The client uses the cursor to get the next page until no more data.

Execution Sample

Rest API

GET /items?limit=3
Response:
{
  "items": ["A", "B", "C"],
  "next_cursor": "cursor123"
}

GET /items?limit=3&cursor=cursor123
Response:
{
  "items": ["D", "E"],
  "next_cursor": null
}

Client requests items in pages of 3. Server returns items and a cursor to get the next page.

Execution Table

Step	Request URL	Server Action	Response Items	Next Cursor
1	/items?limit=3	Fetch first 3 items from start	["A", "B", "C"]	"cursor123"
2	/items?limit=3&cursor=cursor123	Fetch next 3 items after cursor123	["D", "E"]	null
3	/items?limit=3&cursor=null	No more items after last cursor	[]	null

💡 No more items after last cursor, pagination ends

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3
cursor	null	"cursor123"	null	null
items_returned	[]	["A", "B", "C"]	["D", "E"]	[]

Key Moments - 2 Insights

Why does the client send the cursor back to the server?

The cursor tells the server where to continue fetching data. See execution_table step 2 where the cursor "cursor123" is sent to get the next items.

What happens when the server returns a null cursor?

A null cursor means no more data is available. The client stops requesting more pages. See execution_table step 2 and 3 where next_cursor is null.

Visual Quiz - 3 Questions

Look at the execution_table, what is the cursor value after step 1?

A "cursor456"

B "cursor123"

C null

D "start"

💡 Hint

Check the 'Next Cursor' column in execution_table row for step 1

At which step does the server indicate there are no more items?

A Step 3

B Step 2

C Step 1

D None

💡 Hint

Look at the 'Response Items' and 'Next Cursor' columns in execution_table

If the client forgets to send the cursor in step 2, what will happen?

A Server returns an error

B Server returns empty data

C Server returns the first page again

D Server returns all remaining items

💡 Hint

Cursor tells server where to continue; without it, server starts from beginning (see execution_table step 1)

Concept Snapshot

Cursor-based pagination lets clients get data in chunks.
Server returns data plus a cursor pointing to next chunk.
Client sends cursor to get next page.
When cursor is null, no more data.
This avoids skipping or repeating items.
Useful for large or changing data sets.

Full Transcript

Cursor-based pagination is a way to get data page by page from a server. The client asks for a page with a limit. The server sends back the data and a cursor. The cursor is like a bookmark showing where to continue. The client uses this cursor to ask for the next page. This repeats until the server sends a null cursor, meaning no more data. This method helps avoid missing or repeating items when data changes. The execution table shows each request and response with cursors. Variables track the cursor and items returned. Key moments explain why the cursor is sent and what null means. The quiz checks understanding of cursor values and pagination flow.