A key strength of Storybook is its extensibility. Use addons to extend and customize Storybook to fit your team’s development workflow.
Addons are integral to the way Storybook works. Many of Storybook's core features are implemented as addons! These addons are installed out of the box with essentials.
The most obvious thing addons affect in Storybook is the UI of Storybook itself. Within the UI the toolbar and addons panel are the two chief places addons will appear.
Addons can also hook into the rendering of your story in the preview pane via injecting their own decorators.
Finally, addons can affect the build setup of Storybook by injecting their own webpack configuration to allow the use of other tools in Storybook. Addons that do only this are often referred to as presets.
There are many, many Storybook addons, but they can be roughly categorized into three areas: