organizing-streamlit-code

To structure a multi-page Streamlit app, separate UI from business logic by creating a main entry file like streamlit_app.py, moving page interfaces into an app_pages/ directory, and placing non-UI functions into a utils/ module for better readability.

The best way to organize Streamlit project directories is by modularizing code into dedicated modules for data access, UI components, and helpers, which prevents monolithic files and improves overall maintainability and testability.

Refactor a single-file Streamlit app by moving UI elements into streamlit_app.py and app_pages/, while relocating heavy logic and data processing into utils/ to establish a modular, maintainable project layout.

Yes, you can use a modular directory layout to improve Streamlit app testability. Splitting UI, data access, and utilities into clear modules isolates business logic, making it easier to test independently from the interface.

You should modularize your Streamlit code when your app has multiple pages or growing logic. Separating UI from business logic into modules prevents monolithic structures that become hard to maintain and scale.

Placing all Streamlit logic in a single file makes maintenance difficult because it creates a monolithic structure where UI and business logic are tangled, reducing readability and making the codebase hard to test and scale.