Configure a notebook

Configure a notebook’s settings to control its appearance, runtime behavior, and editor preferences.

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Open notebook settings

Notebook settings apply only to the current notebook. You can configure display and export options, add custom CSS and HTML, and change other notebook-specific behavior. To open notebook settings:

1. In the upper-right corner of the notebook, select Notebook Settings ().
2. In the settings menu, change the settings as needed.

To learn more, see marimo’s Notebook settings.

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Configure runtime behavior

Runtime settings control how the notebook responds when it starts, when a cell changes, and when an imported Python module changes.

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Execution modes

The runtime supports the following execution modes:

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Autorun mode

In autorun mode, the notebook automatically runs dependent cells when any of the following events occur:

• You run or edit a cell.
• You interact with a UI element.
• An imported Python module changes while module autoreloading is enabled.

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Lazy mode

In lazy mode, running a cell marks its downstream cells as stale but does not run them automatically. When you run a cell that has stale upstream cells, the notebook runs the upstream cells first. This process ensures that the cell receives up-to-date inputs.

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Change runtime settings

To change the runtime settings:

1. In the notebook footer, select Runtime reactivity ().
2. Configure the applicable settings:

   Setting	Behavior	Options
   On startup	Whether the notebook runs automatically when it starts	Autorun or Lazy
   On cell changes	Whether dependent cells run automatically after a cell runs	Autorun or Lazy
   On module changes	Whether affected cells run when an imported module changes	Off, Autorun, or Lazy

To learn more, see marimo’s Runtime configuration.

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Configure editor preferences

To configure editor preferences:

1. In the upper-right corner of the notebook, select Notebook Settings ().
2. In the settings menu, select Editor.
3. Configure preferences such as code font size, line numbers, and syntax highlighting.

To learn more, see marimo’s Editor features.