The scroll-snap-type property controls whether and how a scroll container will "snap" to certain positions as the user scrolls. It declares that the scrolling viewport should consider the snap positions defined by its children and attempt to land on one of those positions when scrolling finishes, whether the scroll was initiated by touch, mouse wheel, keyboard, or script. In effect, it turns ordinary continuous scrolling into a series of discrete stop points that help users land precisely on content islands like slides, cards, or full-page sections.

Snapping behavior is a cooperation between the container and its children: the container declares that snapping should happen and the children define where the snap points are via scroll-snap-align. The container’s scrollable area, including any inset that should be respected when aligning snap positions, can be adjusted with scroll-padding, and it only takes effect when the element is actually scrollable (which is controlled by overflow). Because snapping uses those child-defined alignment anchors and the container’s padding, you can design layouts where items align to edges, centers, or create custom offsets for the resting position.

From a user-experience and input perspective, snap behavior affects the end-of-scroll settling: it can shorten or extend the final animation after a fling, and it can influence keyboard or programmatic scrolling by guiding where focus lands. That makes snapping valuable for predictable navigation patterns like carousels, page-by-page sections, or step-through previews, but it also means designers must be careful not to interfere with expected scrolling behavior - for example, avoid trapping users in a snap loop or making it harder to reach off-center content. Consider how snapping interacts with inertia on touch devices and with precise wheel or trackpad scrolling so the result feels natural rather than jarring.

In practice, use snapping where clear, repeatable stops improve comprehension and interaction: image galleries, onboarding flows, and paginated content are common places. Avoid overusing it on long, free-form lists where users expect to scan continuously. Test with variable-sized children, different input devices, and assistive technologies; provide alternate navigation controls (buttons, keyboard shortcuts) when snapping is used for essential navigation. Also be mindful of animation performance and layout complexity, since frequent layout adjustments during scroll can have a cost on lower-powered devices.