There's a noteworthy feature on this implementation: the role of VTEX's persistent cart. It is an essential part of the experience since it connects all parts of the buying journey. At the website's header, there's a cart to which the user can add products while navigating. When they click on Proceed to Checkout, the user is redirected to VTEX where shipping calculation, delivery time and all the following steps of the buying journey happen.
The challenge behind this apparently mundane experience was that, during the implementation of this project, all major browsers updated their security policies, which made it impossible to exchange cookies between domains without a server-side configuration. With this limitation, if a user added a product to the cart and then refreshed the page, the cart would be lost, or if they clicked on Proceed to Checkout, the cart would create another session (also losing previously added products) since there's a redirect in-between.
To deliver the experience L'Oréal was looking for, Valtech had to find a way to share a cart session in a stateless piece of software and serve it regardless of which platform the user was on at a given moment of the journey. Fortunately, VTEX has a native persistent cart capability that provides each new cart an ID.