Split URL Testing is the technique to test multiple variations of your website hosted on different URLs. Here, the website traffic is randomly split between the variations, and conversions are tracked to decide which variation performs the best. The variations that you create in a Split URL test are accessed via different URLs, and the performance of each is tracked and analyzed to identify which variation has a better conversion rate for your visitors.
It is recommended to use Split URL Testing when you wish to make some significant design or backend changes (you can do backend changes using VWO Fullstack) on your website. Say you want to test a single page checkout flow vs. a multi-page flow or test a mega menu vs. a dropdown menu, then you can create a Split URL test and host these changes across different URLs to understand and act on the visitors’ behavior. 
The above picture represents how two variations of the example.com domain are hosted on different URLs.
As a rule of thumb, Split URL testing is preferred when you wish to completely redesign each page of your website, while A/B testing is preferred when you want to test minor changes across your website.
Once the Split URL test declares a winner, you can further optimize and redesign your web pages by running an A/B test to test the smaller changes on your web pages.
When a split test is running and visitors land on the original website (the control), VWO either keeps the visitors on the original URL or redirects them to the variation URL. This redirection is done using JS redirect and not by 302 redirects. This is because it helps notify your URL forwarding to the search engines (SEO) and even google guidelines suggest this.
Split URL Testing helps you to:
- Create and run multiple variations of your website on different URLs
- Test different flows and complex changes such as a complete redesign of your website
- Compare webpages hosted on different URLs
- Test a completely new page
A/B vs. Split URL Test
The key difference between an A/B test and a Split URL test is that the variations are hosted on different URLs in the case of the Split URL.
In a typical A/B test, two similar versions with minor changes (as major changes in an A/B test means tests would take a longer time to load) are compared, whereas, in a Split URL test, major changes like redesign are done in the variations. They are then compared to the control version.
To know more about A/B testing in VWO, refer to A/B Testing.
Split URL vs. Multivariate Test
In a Multivariate test, multiple elements on your webpage are modified at a time. Still, the difference between the variation and control is not major, whereas, in a Split URL test, major changes are done in a variation and are tested on different URLs. To know more about Multivariate testing in VWO, refer to Multivariate Testing.
When not to use Split URL Testing?
It will help if you do not use Split URL Testing when you want to test minor changes on your website, like change in the color of the CTA button or change any test change. To test such changes, it’s recommended to use the A/B Testing method. This is because small changes are applied efficiently with an A/B test, whereas a redirect is introduced with the Split URL test.