Streamlit simplifies the process of creating interfaces, displaying text, visualizing data, rendering widgets, and managing web applications from inception to deployment, thanks to its convenient and highly intuitive API, as highlighted in the Appendix. This chapter covers techniques for creating input forms, implementing conditional flows, handling errors, mutating dataframes, and rendering basic charts. After mastering the basics, developers will be equipped to produce, manage, and deploy a range of simple web applications locally. These applications may include data explorers, machine learning tools, multimedia handlers, data wrangling utilities, and other general-purpose solutions. Once comfortable with these fundamentals, developers can move on to creating more advanced and complex applications, which will be explored in subsequent chapters.