What it does
Base Web is the React implementation of the Base design system. Its official repository documents theme providers, TypeScript support and component examples, alongside a notice limiting external engagement.
Base Web implements Uber’s Base design language in React. The package is named baseui, and its setup includes styletron-react and styletron-engine-monolithic. Wrap the application in StyletronProvider, then BaseProvider with a theme such as LightTheme, before adding a component such as StatefulInput.
For more specific changes, the overrides property can alter a subcomponent’s styles, properties or implementation. A style function can use $theme and states such as whether a list item is being dragged. The guide warns against mixing shorthand and longhand CSS properties in overrides, and replacing an entire subcomponent also replaces its original styling.
The toolkit is free under MIT and public package installation needs no account. Its maintenance notice remains relevant: Uber continues mirroring internal development while limiting external engagement. Heavy behaviour overrides also make future upgrades harder and may fall outside the maintainers’ ability to help.
Strengths
- A documented React implementation supplies shared themes and components.
- TypeScript and component examples are part of the official adoption material.
- Overrides expose styling, properties and state-aware customization of subcomponents.
Watch out for
- The repository explicitly limits external engagement while mirroring internal development.
- Replacing or deeply overriding component behaviour can complicate upgrades.
Best for
- Teams evaluating or maintaining interfaces based on the Base design language
Sources
- uber/baseweb (Oct 27, 2026)
- Understanding overrides | Base Web (Oct 27, 2026)