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

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

width · 'normal' | 'medium' | 'full' · default: "'normal'"

Controls the width of the notebook layout

app_title · str

Title displayed in the browser tab

css_file · str

Path to custom CSS file for styling

Decorators

@app.cell

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

@app.cell
def cell_name():
    # Cell code here
    x = 1
    y = 2
    return x, y

hide_code · bool · default: "False"

Whether to hide the cell code in app mode

disabled · bool · default: "False"

Whether the cell is disabled

Running Apps

Apps can be run in three modes:

1. Edit mode: Interactive development environment

marimo edit notebook.py

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

marimo run notebook.py

3. Script mode: Execute as a Python script

python notebook.py

Programmatic Execution

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.

app.export_html("output.html")

ASGI Integration

Create an ASGI app for deployment:

from marimo import create_asgi_app

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

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

Related

Cell

Learn about marimo cells

Creating Notebooks

Guide to creating marimo notebooks