Advanced4 steps

How to Handle Infinite Scroll When Scraping

Infinite scroll pages load new content dynamically as the user scrolls down — meaning a standard HTTP fetch only returns the initially visible content. Collecting the full dataset requires either simulating scroll actions or intercepting the underlying data requests.

Step-by-Step Guide

1

Check for a hidden API endpoint first

Open browser DevTools → Network tab and filter for XHR/Fetch requests while scrolling. Many sites load infinite scroll data from a clean JSON API endpoint — fetching that directly is faster than scraping the HTML.

2

Use JavaScript rendering with scroll simulation

If no clean API endpoint exists, use AlterLab with render_js enabled. Some targets support a scroll parameter that triggers additional content to load.

3

Extract a cursor or offset from each response

Infinite scroll content typically includes a cursor, next_cursor, or offset field in either the HTML data attributes or the underlying API response. Extract this to construct the next request.

4

Loop until no more content is returned

Continue fetching with the updated cursor until the response returns an empty results list or no next_cursor value.

Code Example

import requests

def scrape_paginated_api(base_url: str, api_key: str) -> list[dict]:
    """For sites with a discoverable JSON API endpoint."""
    results = []
    cursor = None

    while True:
        params = {"limit": 20}
        if cursor:
            params["cursor"] = cursor

        response = requests.post(
            "https://alterlab.io/api/v1/scrape",
            headers={"X-API-Key": api_key, "Content-Type": "application/json"},
            json={"url": f"{base_url}?{'&'.join(f'{k}={v}' for k,v in params.items())}"},
        )
        data = response.json()
        items = data.get("items", [])
        results.extend(items)
        cursor = data.get("next_cursor")
        if not cursor or not items:
            break

    return results

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terminal
curl -X POST https://api.alterlab.io/v1/scrape \
-H "X-API-Key: YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{"url": "https://example.com", "formats": ["markdown"]}'

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    How to Handle Infinite Scroll Web Scraping | AlterLab | AlterLab