> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/marimo-team/marimo/llms.txt
> Use this file to discover all available pages before exploring further.

# App

> Create and run marimo applications

# mo.App

The `App` class is the core container for marimo notebooks. It represents a collection of cells that form a reactive computational graph.

## Overview

A marimo app is created using the `@app.cell` decorator to define cells. The app manages the reactive execution of cells based on their dependencies.

## Creating an App

```python theme={null}
import marimo

__generated_with = "0.20.3"
app = marimo.App(width="medium")


@app.cell
def __():
    import marimo as mo
    return mo,


@app.cell
def __(mo):
    name = mo.ui.text(placeholder="Enter your name")
    name
    return name,


@app.cell
def __(mo, name):
    mo.md(f"Hello, {name.value}!")
    return
```

## App Configuration

<ParamField path="width" type="'normal' | 'medium' | 'full'" default="'normal'">
  Controls the width of the notebook layout
</ParamField>

<ParamField path="app_title" type="str">
  Title displayed in the browser tab
</ParamField>

<ParamField path="css_file" type="str">
  Path to custom CSS file for styling
</ParamField>

## Decorators

### @app.cell

Defines a cell in the marimo app. Cells are executed reactively based on their dependencies.

```python theme={null}
@app.cell
def cell_name():
    # Cell code here
    x = 1
    y = 2
    return x, y
```

<ParamField path="hide_code" type="bool" default="False">
  Whether to hide the cell code in app mode
</ParamField>

<ParamField path="disabled" type="bool" default="False">
  Whether the cell is disabled
</ParamField>

## Running Apps

Apps can be run in three modes:

1. **Edit mode**: Interactive development environment

```bash theme={null}
marimo edit notebook.py
```

2. **Run mode**: View-only app with optional code hiding

```bash theme={null}
marimo run notebook.py
```

3. **Script mode**: Execute as a Python script

```bash theme={null}
python notebook.py
```

## Programmatic Execution

```python theme={null}
from marimo import App

app = App()

@app.cell
def __():
    import marimo as mo
    return mo,

# Run the app
if __name__ == "__main__":
    app.run()
```

## App Methods

### app.run()

Execute the app as a script. This runs all cells in dependency order.

### app.export\_html()

Export the app to a standalone HTML file.

```python theme={null}
app.export_html("output.html")
```

## ASGI Integration

Create an ASGI app for deployment:

```python theme={null}
from marimo import create_asgi_app

# Create ASGI app from notebook file
asgi_app = create_asgi_app()
    .with_app(path="/", root="notebook.py")
    .build()
```

<Tip>
  Apps are stored as pure Python files, making them git-friendly and executable as scripts.
</Tip>

## Related

<CardGroup cols={2}>
  <Card title="Cell" icon="square" href="/api/cell">
    Learn about marimo cells
  </Card>

  <Card title="Creating Notebooks" icon="plus" href="/creating-notebooks">
    Guide to creating marimo notebooks
  </Card>
</CardGroup>