> ## Documentation Index
> Fetch the complete documentation index at: https://genai.codewithsiva.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Learn what Streamlit is, how it works, and how to build your first app

Streamlit helps you turn Python scripts into interactive web apps without writing HTML, CSS, or JavaScript.

## What is Streamlit?

Streamlit is an open-source Python library for building dashboards, data tools, and AI demos. It is especially useful when you want to share a notebook-like workflow with non-technical users.

You can use it to create:

* AI chat interfaces
* Data dashboards
* Simple internal business tools
* Prototype applications for machine learning projects

## Streamlit architecture

Streamlit follows a simple client-server model:

1. Your Python script runs on the server.
2. The browser shows the interface.
3. When a user interacts with a widget, the browser sends a new event to the server.
4. Streamlit reruns the script to refresh the page with the latest values.

## Execution flow

Streamlit uses a rerun model. Every time a user clicks a button, types in a field, or changes a slider, the script runs again from top to bottom. This makes the app feel reactive and keeps the UI in sync.

```python theme={null}
import streamlit as st

st.title("Hello Streamlit")
name = st.text_input("Your name")

if name:
    st.write(f"Hello, {name}!")
```

## Creating and running an application

Create a file such as `app.py` and run it from your terminal:

```bash theme={null}
streamlit run app.py
```

This starts a local server, usually at `http://localhost:8501`, and opens your app in the browser.

## Project structure

A simple Streamlit project often contains:

* `app.py` for the main app logic
* `data/` for CSV or JSON files
* `images/` for local media files
* `pages/` for multipage apps

## A practical learning path

The Streamlit module is organized into five beginner-friendly sections:

<CardGroup cols={2}>
  <Card title="Displaying content" icon="eye" href="/streamlit/displaying-content">
    Render text, tables, images, and status messages
  </Card>

  <Card title="User input widgets" icon="sliders" href="/streamlit/widgets">
    Collect text, selections, files, and dates
  </Card>

  <Card title="Layouts and interactivity" icon="grip" href="/streamlit/layout">
    Organize your app with sidebars, tabs, and forms
  </Card>

  <Card title="Working with data" icon="table" href="/streamlit/data-handling">
    Load CSV files, filter rows, and visualize data
  </Card>
</CardGroup>