What is the difference between Fast and FullJS drivers?

Fast and FullJS drivers load pages differently. Use Fast when the data is already present in the returned HTML. Use FullJS when the website needs JavaScript or browser interaction.

Fast driver

Fast driver extracts data from the HTML returned by the website without running page JavaScript.

Works at roughly twice the speed of FullJS.
Best for pages where the required data is already present in the returned HTML.
Does not support browser interactions that require JavaScript execution.

FullJS driver

FullJS loads the page in a browser environment and executes JavaScript before extraction.

Use FullJS when the sitemap or website requires:

JavaScript-rendered content
Scrolling
Element Click selectors
Website Log-In / State setup
Other browser interactions

When Fast cannot be selected

Web Scraper Cloud does not allow Fast driver when the sitemap contains:

Scrolling
Element Click selectors
Website State Setup
Pagination using Click multiple times or Click once
Pagination using Link from any script

Which driver should I use?

Keep the default FullJS driver when JavaScript behavior is required. If the sitemap is compatible with Fast, run a Test scrape and compare the returned records and required fields before using Fast for production jobs or schedules.

If Fast can be selected but the website loads important data with JavaScript, the job may return missing or Empty data.

See the Fast driver and FullJS driver documentation for more information.