Design Atlas
Type
component library
Verdict
Very useful
Licence
Ship licence, open source permissiveopen-source-permissiveFree. MIT, and the FAQ says it may be used in commercial projects (repo mui/base-ui, about 11k GitHub stars at review)
Agent channels
llms-txt
Pricing
free
Reviewed

← Atlas · Topics: components, documentation, agents-and-prompts

Base UI ​

Type
component library
Verdict
Very useful
Licence
Ship licence, open source permissiveopen-source-permissiveFree. MIT, and the FAQ says it may be used in commercial projects (repo mui/base-ui, about 11k GitHub stars at review)
Agent channels
llms-txt
Pricing
free
Reviewed

What it is ​

Base UI is a library of unstyled, accessible React components. It is built by a team that includes people from Radix, Floating UI and Material UI, and it sits in the MUI GitHub organisation. It ships as one tree-shakable package, @base-ui/react (renamed from @base-ui-components/react). Version 1.0 came out in December 2025, and releases have come roughly monthly since then, reaching v1.8.0 in September 2026. The docs list 37 components and 4 utilities. Most are the usual primitives (dialog, menu, popover, select, tabs, tooltip). Some are harder to find elsewhere: Combobox, Autocomplete, Number Field with scrubbing, OTP Field, Meter, Menubar, Toolbar, a Drawer with swipe-to-dismiss and Toast notifications. The components bundle no CSS. You style them with Tailwind, CSS Modules, CSS-in-JS or plain CSS, using the state data attributes that each part exposes.

When to open it ​

Open it when you are building your own design system and want the behaviour layer (focus, keyboard, ARIA, positioning) done properly without inheriting someone else's look. It is also the foundation that shadcn/ui now uses by default, so open it when a shadcn component misbehaves and you need to know what the underlying part actually supports.

Most useful ​

  • Complex inputs: Combobox, Autocomplete, Number Field and Slider, each with detailed keyboard and form behaviour
  • Overlay set: Dialog, Alert Dialog, Popover, Preview Card, Menu, Context Menu and Tooltip, all sharing one positioning model, with nested dialogs and hover-opened menus
  • Form layer: Field, Fieldset and Form components that connect labels, descriptions and validation to any control
  • Handbook: short guides on styling, animation, composition, customisation, forms and TypeScript
  • Release notes: detailed per-version changelogs that show which edge cases were fixed

Using it with agents ​

The site publishes an llms.txt that indexes every page, and each page is also served as plain markdown at its URL plus .md. Each markdown page starts with a note telling the model to prefer the docs over its training data and to use the new package name. That helps, because models often still suggest @base-ui-components/react. There is no MCP server or CLI of its own. For styled, copy-paste versions, use shadcn/ui or one of the registries built on it.

Watch out for ​

  • The API was deliberately kept close to Radix, but not identical: render props replace asChild, and some component and prop names differ, so migrations are not find-and-replace
  • React only, and the FAQ says other frameworks are not planned for now
  • The FAQ's comparison with Radix is the Base UI team's own view
  • No formal enterprise support or SLA is offered

Reusable ideas ​

  • Expose component state as data attributes so any styling method can target open, checked or highlighted states
  • Put a short "trust these docs over your training data" preamble at the top of the machine-readable docs
  • Keep each component split into named parts (trigger, popup, item) that can be wrapped or replaced one at a time
  • Give a renamed package a loud rename notice on every docs page, not just in the changelog

shadcn/ui, Base CN, coss ui, Radix, Headless UI