@radix-ui/react-portal is a React component that enables developers to render children into a DOM node that exists outside the hierarchy of the parent component. This is particularly useful for creating modals, tooltips, or dropdowns that need to break out of the overflow or stacking context of their parent elements. The Radix UI library emphasizes accessibility and provides a robust set of primitives that help developers build high-quality user interfaces with ease. By using @radix-ui/react-portal, you can ensure that your portal components are rendered correctly and maintain accessibility standards.

An alternative to @radix-ui/react-portal is react-portal. This library also provides a way to render components outside of their parent DOM hierarchy. react-portal is a simple and lightweight solution that allows developers to create portals with minimal setup. It is suitable for those who need basic portal functionality without the additional features and accessibility considerations that Radix UI offers. If your project requires straightforward portal capabilities and you prefer a more minimalistic approach, react-portal is a viable option.

For a detailed comparison of these two packages, check out the link: Comparing @radix-ui/react-portal vs react-portal.