PageCrawl uses real headless browsers to render web pages, executing JavaScript and loading dynamic content exactly as a visitor would see it. You can choose between three engine modes depending on the page you are monitoring.
Available Engines
| Engine | Best For | How It Works |
|---|---|---|
| Default | Most websites | Standard headless browser with full JavaScript rendering |
| Stealth | Bot-protected pages | Anti-detection mode that bypasses Cloudflare, DataDome, and similar protections |
| Fast | Static pages, speed | Lightweight HTTP client without a browser, faster and uses fewer resources |
Default Engine
The default engine uses a real headless browser to load pages. It processes JavaScript, waits for dynamic content, handles cookies, and renders the page as a real user would see it. This works for the majority of websites.
Stealth Mode
Some websites use bot detection services (Cloudflare, DataDome, and similar) that block standard headless browsers. Stealth mode uses additional anti-detection techniques to appear as a regular browser visit.
PageCrawl automatically switches to Stealth mode when a page is blocked (Cloudflare timeout, 403 Forbidden, or 401 Unauthorized). You can also enable it manually per page.
Fast Mode
Fast mode uses a lightweight HTTP client instead of a full browser. It does not execute JavaScript or render the page visually, making it significantly faster and more resource-efficient. Use this for:
- Static HTML pages that do not rely on JavaScript
- API responses and JSON endpoints
- Pages where you only need text or HTML content
- High-frequency monitoring where speed matters
Fast mode supports Full Page, Text, HTML, Number, Price, Boolean, Availability, Links, and PDF element types. It does not support Visual comparison, screenshots, or actions (click, scroll, type).
Choosing the Right Engine
| Scenario | Recommended Engine |
|---|---|
| Standard website | Default |
| JavaScript-heavy SPA | Default |
| Cloudflare-protected page | Stealth |
| Page returning 403 or timeouts | Stealth |
| Static HTML page | Fast |
| API or JSON endpoint | Fast |
| Need screenshots or visual diff | Default or Stealth |
| High-frequency checks (every 5 min) | Fast (if page allows) |
Configuration
Set the engine per page in the page editor under Power User settings, or apply it in bulk via Bulk Edit.
Related Articles
- Monitoring Pages Behind Cloudflare - Handling anti-bot protections
- Custom Proxies - Use your own proxy servers
- Advanced Configuration - Power User mode and engine selection