Portal

Renders its children into a DOM node outside the parent component hierarchy - the document body by default. Used by overlay components (Modal, Drawer) so their content escapes ancestor overflow/transform/stacking contexts.

Resolution is synchronous during render, so the portaled content mounts in the same commit as the <Portal> - consumers can rely on their root ref being attached before their effects run. On the server (no document) it renders nothing, so what an overlay draws in a portal - a modal, a drawer, a popover, a menu, a tooltip, a snackbar, a list of suggestions - is absent from server-rendered and prerendered HTML and mounts on the client when it opens. An overlay that starts open is closed in the static HTML and opens on hydration; its trigger renders as usual.