Flow Stack separates navigation state from scene rendering so each stack can live wherever your interface needs it.

Building blocks

Concept	Description
Provider	Owns the stack state. One per independent navigation context.
Screen	Declares a named route and its component.
Viewport	Renders the visible scenes and runs transitions. Separate from the provider so you can position it freely.
Scene	Individual scene container rendered by the viewport. Exposed for custom renderScene implementations.
Controller	The headless state machine. The provider wraps one internally; you can also create one directly.
useNavigationStack	Hook that gives any component inside the provider access to push, pop, replace, reset, and the current state.

Transition resolution order

Transitions are resolved in priority order: action options → route-level transition → stack-level transition → built-in fallback. Timing fields (duration, easing, enterCurve, exitCurve, stagger) and style fields (preset, translate, opacity, scale) are merged independently, so you can mix a string preset at the route level with a custom duration at the stack level.

Multiple independent stacks

Mount as many NavigationStackProvider instances as you need — each is fully isolated and identified by its id. When more than one stack is mounted, useNavigationStack(stackId) and <NavigationStackViewport stackId="..."> target a specific stack instead of the nearest provider.

Next: Provider guide · Viewport guide