When do I need a headless browser vs simple HTTP requests?
Headless browsers are powerful but slow and expensive. Use them only when necessary.
Simple HTTP requests (Requests/Axios):
When to use:
- Static HTML sites
- Server-side rendered content
- Public APIs
- Pages where all content is in initial HTML response
- Cost and speed are priorities
Advantages:
- 10-100x faster than headless browsers
- Much lower resource usage
- Simpler code and debugging
- Lower bandwidth costs
- Easier to scale
Headless browsers (Puppeteer/Playwright/Selenium):
When to use:
- JavaScript-rendered content (SPAs built with React, Vue, Angular)
- Content loaded after page load (infinite scroll, lazy loading)
- Sites requiring user interaction (clicking, scrolling, form submission)
- Sites with aggressive bot detection
- Need to take screenshots or generate PDFs
Disadvantages:
- 10-100x slower
- High memory and CPU usage
- More complex setup and maintenance
- Higher bandwidth costs (loads all assets)
- Harder to debug
How to decide:
Step 1: Check if content is in initial HTML
- View page source (right-click → View Page Source)
- If you see your target data: Use HTTP requests
- If you see
<div id="root"></div>or empty containers: Might need headless
Step 2: Check network requests
- Open DevTools → Network tab
- Look for API endpoints returning JSON
- If data comes from APIs: Scrape the API directly (fastest option)
Step 3: Test with simple requests first
- Always try HTTP requests before assuming you need a browser
- Many "dynamic" sites actually have server-side rendering
Hybrid approach:
Some scrapers use both:
- HTTP requests for product listing pages (fast)
- Headless browser for detail pages with dynamic reviews (when needed)
Cost comparison:
Scraping 10,000 pages:
- HTTP requests: $5-20 (mostly proxy costs)
- Headless browser: $50-200 (10x bandwidth + compute costs)
Recommendation:
Start with simple HTTP requests. Only use headless browsers after confirming:
- Content is truly JavaScript-rendered
- No API endpoint is available
- The added cost and complexity is justified