Prestahop is a free, feature-rich, and open-source E-commerce solution. It is supposed to be installed, not run "hosted" in the cloud. Prestahop is used by many shops worldwide and is available in many different languages. It may demand a bit of work to launch your online store, but it comes with impressive features and functionalities.
When you are reading this article, you most likely have a problem with your Prestahop installation, namely that all product pages redirect to a 404 page. After changing the "Schema of URLs" in Prestahop 1.7.* to show more friendly URLs to visitors and search engines, your product pages can stop working all together, and all you will see is the 404 page. the Prestahop default Schema of URLs is hard to find, and just changing it until it works can require a lot of patience.
To fix this issue, make sure you disable "Friendly URL", clear the cache, and turn "Friendly URL" on again. That way, the .htaccess gets recreated. After that, make sure to put the "Route to products" to the following:
:id_product_attribute is mandatory; without it, your product pages will not work.