building-streamlit-multipage-apps

Build a multipage Streamlit app by creating a centralized streamlit_app.py entrypoint that initializes shared session state, defines navigation using st.navigation, and runs selected page modules. Page modules remain focused on content while the entrypoint handles routing and shared UI state.

Session_state management across Streamlit pages requires initializing global keys in the main entrypoint module and using prefixed keys for page-specific state to avoid collisions. This pattern ensures consistent state initialization and prevents duplicated UI or brittle imports across pages.

Organize Streamlit multipage page modules by creating a dedicated app_pages directory structure. The main streamlit_app.py entrypoint constructs navigation over this directory, keeping page code modular and focused on content while the entrypoint handles shared widgets and routing.

Switch Streamlit pages programmatically using st.switch_page, which supports building conditional page lists based on authentication, user roles, or feature flags. This enables dynamic navigation control where available pages change based on application state or permissions.

Use top navigation in Streamlit for small apps with few pages, and sidebar or grouped navigation for apps with many pages. Mixed ungrouped sections are also supported, allowing flexible navigation strategies that scale with application complexity.

A single entrypoint file like streamlit_app.py is needed to manage navigation in Streamlit multipage apps. It centralizes session_state initialization, defines the navigation structure, displays shared UI like titles, and calls page.run() to render the selected page module.