using-streamlit-session-state

You persist data across Streamlit reruns by storing values in the st.session_state dictionary, which survives script reruns and prevents variables from resetting on every user interaction.

Streamlit widget values reset because the framework reruns the entire script on every interaction. Binding widgets by assigning a key automatically syncs their values with st.session_state to maintain persistence.

You share data across Streamlit pages by reading and writing variables to the st.session_state dictionary, allowing state variables to be accessed and updated globally across different pages of the webapp.

The best way to initialize default state in Streamlit is using st.session_state.setdefault at the top of the app, which establishes clear state defaults before the script executes further rerun logic.

Yes, you can modify Streamlit session state before a rerun by using on_change and on_click callbacks, which let you execute logic and update state values immediately before the script reruns.

Yes, st.session_state works for interactive counters in Streamlit by storing the count value in the persistent dictionary and incrementing it via button clicks, ensuring the value persists across reruns.