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How do you handle API pagination when fetching data?

Anubhav Sharma 951 06 Nov 2025

How do you handle API pagination when fetching data?

1 Answers

ICSM Computer 18 Nov 2025

1. Understand the Pagination Type

Different APIs use different pagination styles. Common ones:

Offset-based pagination
Example: /products?limit=20&offset=40
You fetch the next page by increasing the offset.
Page-based pagination
Example: /products?page=3&pageSize=20
You increment the page number.
Cursor-based pagination (recommended for large data)
Example: /products?cursor=abc123
API returns a nextCursor to fetch the next batch.
Token-based / Continuation Token
Used in cloud APIs (Azure, AWS).
Example: ?continuationToken=xyz.

2. Handle Pagination Loop

Keep fetching data until there is no next page.

Example Logic:

var allItems = new List<Item>();
string nextPage = "1";

while (!string.IsNullOrEmpty(nextPage))
{
    var response = await Api.GetData(nextPage);

    allItems.AddRange(response.Items);

    nextPage = response.NextPage;   // could be page, offset, cursor, token
}

3. Handle Limits and API Constraints

When implementing pagination:

Respect rate limits (429 Too Many Requests)
Use async to avoid blocking
Implement backoff retries (e.g., 1s → 2s → 4s)
Keep page size reasonable (20–100 items)

4. Example JSON Response from a Paginated API

{
  "items": [...],
  "page": 2,
  "pageSize": 20,
  "hasMore": true,
  "nextPage": 3
}

5. (Frontend UI)

Here is how to handle API pagination using JavaScript, with clean, production-ready examples for all common pagination types.

1. Page-based Pagination (page=1,2,3...)

async function fetchAllPages() {
  let page = 1;
  let allData = [];
  let hasMore = true;

  while (hasMore) {
    const res = await fetch(`/api/products?page=${page}&pageSize=20`);
    const data = await res.json();

    allData.push(...data.items);

    hasMore = data.hasMore;       // API flag
    page++;
  }

  console.log(allData);
}

2. Offset-based Pagination (limit & offset)

async function fetchWithOffset() {
  let offset = 0;
  const limit = 20;
  let allItems = [];

  while (true) {
    const res = await fetch(`/api/products?limit=${limit}&offset=${offset}`);
    const data = await res.json();

    allItems.push(...data.items);

    if (data.items.length < limit) break; // No more pages

    offset += limit;
  }

  console.log(allItems);
}

3. Cursor-based Pagination (most scalable)

API response example:

{
  "items": [...],
  "nextCursor": "abc123"
}

JavaScript code:

async function fetchCursorPagination() {
  let cursor = null;
  let allItems = [];
  let url = "/api/list?limit=20";

  while (true) {
    const res = await fetch(cursor ? `${url}&cursor=${cursor}` : url);
    const data = await res.json();

    allItems.push(...data.items);

    if (!data.nextCursor) break; // No more pages
    cursor = data.nextCursor;
  }

  console.log(allItems);
}

4. Pagination With Async/Await + Error Handling

async function safeFetch(url) {
  try {
    const response = await fetch(url);

    if (!response.ok) {
      throw new Error(`HTTP: ${response.status}`);
    }

    return await response.json();
  } catch (err) {
    console.error("API Error:", err);
  }
}

5. Infinite Scroll (Frontend UI)

let page = 1;
window.addEventListener("scroll", async () => {
  if (window.innerHeight + window.scrollY >= document.body.offsetHeight) {
    const res = await fetch(`/api/products?page=${page++}`);
    const data = await res.json();

    data.items.forEach(item => {
      document.querySelector("#list").innerHTML += `<li>${item.name}</li>`;
    });
  }
});

6. Best Practices

Always check for hasMore or nextCursor
Use cursor-based pagination for real-time, large lists
Cache data where possible
Optimize your UI to load lazily (infinite scroll)

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