Adaptive design is a web design approach where several fixed layouts are created to fit different screen sizes. This ensures that a website's layout and content adjust and optimize themselves for viewing on any device, from smartwatches to mobile devices and TVs. When a user opens the site, the system detects the screen size and selects the closest layout to display.
Adaptive design gives the UX designer more control over the content of each layout. User experience can be optimized for a unique experience across devices. For example, a hotel may notice that guests are more likely to make a reservation on their phones. They might want to streamline the reservation process on their mobile site, while the desktop site provides more information and detail.
Another advantage to adaptive sites is that they only contain code related to a given screen size, making load times quicker in comparison to responsive sites.
However, adaptive designs can be time-consuming, since designers will have to create separate unique layouts and maintain each. Resource contraints restrict designers to a few layouts. The limitation means that users with uncommon screen sizes will likely not have a format meant for them.