Best of

Free is the default in this space, which makes the word almost useless on its own. What matters is what it hides. Some libraries are free in every sense; others are free until you need a virtualised data grid or a page template, and those are filed as Freemium here so this list stays honest. Licence text matters more than price: Canvas UI is MIT with a Commons Clause, React Aria and Carbon are Apache-2.0 rather than MIT, and Polaris ships under Shopify's own terms. Everything below has no paid tier at all.

The honest answer to this question is uncomfortable: almost nothing here is a true server component library. Interactive components need state, effects and event handlers, and all three make a component a client component. A dropdown that opens cannot run on the server. What actually varies is how gracefully a library handles the boundary. The ones listed here work cleanly inside an App Router project without a wrapper you write yourself. Everything else in this directory still works with React Server Components; it just needs an explicit client boundary you own.

A Figma kit is only worth something if it stays in sync with the code. Most do not: the kit ships at launch, the library moves on, and within two releases designers are handing over screens developers cannot build. The libraries here split into two groups. Some treat the kit as a marketing asset; others derive the code from the design file, so drift is impossible by construction. Before committing a design team, compare the kit's last update date with the library's last release. That one check tells you which group you are in.

An MCP server lets your coding assistant read a library's real documentation instead of recalling it from training data. That matters most at version boundaries, where an assistant working from memory writes confident code against an API that no longer exists: Chakra v2 to v3, Fluent v8 to v9, NextUI to HeroUI. Depth varies a lot, so read each entry rather than treating the badge as equal everywhere. Some expose documentation only; shadcn/ui makes its server registry-aware, HeroUI runs a second one just for migrations, and Mantine adds agent skills on top. One pattern is worth noticing: the headless primitive layers publish almost none of these.

Tailwind won the styling argument for a large part of the front end, and a whole tier of component libraries now assumes it. The practical benefit is that theming stays in one config: change your palette or spacing scale and the components follow, with no styling runtime shipped. The catch is lock-in of a different kind. Drop Tailwind later and these components stop looking like anything.

Most libraries claim accessibility somewhere in their README. The ones here document it: published ARIA patterns, keyboard interaction tables, focus management, and in several cases real screen reader testing. That matters beyond good intentions, since public sector procurement increasingly requires it in writing. Picking from this list will not make a product accessible on its own, because colour contrast, heading order and form labelling stay yours. It does mean the hard parts, the ones almost nobody reimplements correctly, are already handled.

These are not dependencies. A CLI writes component source straight into your repository, and from that moment the code is yours: you edit it, you version it, you own the breaking changes. shadcn/ui made the pattern popular and a shared registry format grew around it, so kits from different authors now install with the same command. The upside is never fighting an abstraction to change one border radius. The downside is that upgrades are manual, because there is no package to bump.

A headless library ships behaviour and no appearance: focus traps, keyboard navigation, ARIA attributes, state machines. You write every line of CSS yourself. That trade pays off when you already have a design system and every styled library fights it, or when one accessibility layer has to serve several themes. The cost is real, though: a headless dropdown looks like nothing until you make it look like something.