A multi-session conversion occurs when visitors make several successive visits to a website before completing a desired action, such as a purchase. This type of conversion is common in contexts where purchasing decisions are complex or involve significant sums of money, or when the decision is made collectively. For example, multi-session conversions are frequent in the tourism industry.

To conduct effective A/B testing in an environment characterized by multi-session conversions, it is essential that an individual is exposed to the same version or variant of the website during their different visits. This continuity is ensured through the use of a specific system.