> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rixxui.com/llms.txt
> Use this file to discover all available pages before exploring further.

# React 18 and React 19

> Supported React versions, rendering behavior, Strict Mode, SSR, and hydration guidance.

`@rixx-ui/react` and `@rixx-ui/react-devtools` support React and React DOM
`^18.2.0 || ^19.0.0`.

## Shared guidance

* Import renderer styles once at the application root.
* Keep accumulated source and stream status in host state.
* Pass deterministic `options` on both server and client.
* Treat callbacks as notifications; keep effects and authorization in host code.
* Use stable `surfaceId` values when the host needs stable event correlation.

## React 18

Use `createRoot` for client applications and the standard React 18 streaming SSR
APIs when rendering on the server. Rixx UI uses `useSyncExternalStore` to expose
consistent source-store snapshots.

## React 19

The same component API is supported. Rixx UI does not require React 19-only
features, so applications can upgrade independently. Preserve normal Client
Component boundaries in frameworks that distinguish server and client modules.

## Strict Mode

Development Strict Mode may repeat render/effect lifecycles. Host action
execution must already be idempotent and tied to explicit user interaction.
Never execute an action simply because an event-bearing component rendered.

For SSR, remember that Mermaid diagrams are committed, sanitized rich content
and may complete their visual rendering on the client. Provide identical source,
catalog, and renderer options during hydration.