# Manage shared state

Effective management of the shared state is a crucial aspect of a federated application and can become problematic if not handled carefully. As a general rule, a host application and its modules should never share state.

# Forward the initial data

However, at certain points in the lifecycle of a federated application, the host will fetch initial data that should be fordwarded to the modules. Such examples include a user session and a user tenant subscription status:

• To forward a user session object, a built-in sessionAccessor function is available.

• To forward other types of initial data, such as a user tenant subscription, as shown in the Fetch initial data guide, the data can be forwarded to modules through a React context.

# React Query

Lastly, as detailed in the fetch page data guide, the React Query cache should not be shared between the host and its modules. To do so, both the host application and the modules should instantiate their own QueryClient instance.