How to A/B test landing pages with auto-swapping of pages in random order?

Question

CMS

Good afternoon,
we have created two landing pages (2 landing pages). We plan to organize A / B testing of user behavior on the site. How can I automatically change page rotation for new users? Roughly speaking, user A sees page A, user B sees page B, user C sees page A, and so on. In this case, it is desirable to display the previous version of the page to the same user when updating the page.
Share your experience on how this can be organized and whether there are ready-made solutions for this. It is desirable to immediately have a ready-made code and instructions on which you can organize it.

Answer 1

It is easier to advertise on different pages directly, so that there is no headache with calculations. Well, on these different pages, put other data (you can make 1 index.php with different $ _GET some so that they are processed correctly and substitute the necessary data). In our company, 40 pages are spinning almost identical.