You don't need a powerful tool like Google Optimize for simple URL split tests; you can also implement a split test with Apache using .htaccess. The following code snippet distributes visitors from the two pages https://vielhuber.de/test1.php (Variant 1) and https://vielhuber.de/test2.php (Variant 2) evenly between both versions. The randomization is based on the current server time.
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Returning visitors always see the website last viewed (via session cookie). The concept can easily be expanded to include several variants or a central URL that is distributed to sub-pages.