browser

Server-Side Rendering

Server-side rendering (SSR) generates HTML on the server for each request, delivering fully populated markup to the client without requiring JavaScript execution — making content directly accessible to HTTP scrapers.

In SSR, the web server generates a complete HTML document — with all content populated — and sends it to the browser. The browser renders the HTML immediately, providing fast initial load and making all content visible to crawlers and scrapers that only fetch the HTML source. This contrasts with client-side rendering (CSR/SPA), where the server sends a minimal HTML shell and JavaScript populates the content after execution.

For scrapers, SSR pages are the easiest to work with: fetch the URL with an HTTP client and parse the HTML — no JavaScript execution required. Next.js, Nuxt.js, and SvelteKit support SSR as a rendering mode. Many e-commerce and news sites use SSR for product and article pages to ensure content is indexed by search engine crawlers.

AlterLab's Tier 1 engine (HTTP-only) is sufficient for SSR pages. When a site migrates from SSR to CSR/SPA without notice, scrapers begin receiving empty HTML shells and must be upgraded to a browser-based tier.

Examples

# SSR page: plain HTTP fetch is sufficient — content is in the HTML
import requests
from bs4 import BeautifulSoup

response = requests.get("https://ssr-site.com/product/123")
soup = BeautifulSoup(response.text, "html.parser")
price = soup.select_one(".product-price")
print(price.text if price else "Not found")