runtime

The web runtime is powered by Starlette and Uvicorn with persistent WebSockets.

session isolation

Each browser connection initializes an isolated Session object. The session maintains its own component tree, active route, reactive state store, and event bindings.

streamlit-tier granular hot reload

During development (shadlet dev), shadlet watches the workspace for Python source modifications using watchfiles: - File system write events are debounced with a minimum cooldown threshold (300ms) to prevent multi-fire churn. - When changes occur, session.refresh() re-evaluates the view tree and generates granular diff patches (set_prop, replace_node, insert_child, remove_child). - Updates are transmitted over the active WebSocket, instantly updating only the changed DOM nodes without resetting client-side state or triggering a full browser refresh.

disconnect recovery

If the connection is interrupted: - A full-width banner appears at the top of the interface indicating that the server disconnected. - The client automatically retries connecting using exponential backoff (starting at 400ms up to 3s). - Users can also trigger immediate reconnection using the interactive button in the banner.