Introduction
Why Headless UI Libraries matter in modern React
Modern frontend development has shifted heavily toward custom design systems. Teams no longer want off-the-shelf UI kits that dictate colors, spacing, and layout. Instead, they want full control over styling while still getting:
- Accessibility done right
- Predictable behavior
- Cross-browser consistency
- Composable APIs
This is where headless UI libraries come in.
A headless UI library focuses on logic, state management, accessibility, and interactions, while leaving styling entirely up to the developer. This approach works especially well with:
- Tailwind CSS
- Custom design systems
- shadcn-style component architectures
Rather than fighting predefined styles, developers can build exactly what they need—without re-implementing complex behaviors like keyboard navigation, focus management, or ARIA roles.
The rise of Radix UI and Base UI
Among headless UI libraries in the React ecosystem, Radix UI and Base UI have gained significant attention—but for different reasons.
- Radix UI became popular by offering:
- Production-ready components
- Strong accessibility defaults
- A stable, well-documented API
- Minimal styling, but clear structure
- Base UI, on the other hand, takes a more primitive-first approach:
- Extremely low-level building blocks
- Maximum control over the DOM structure
- Fewer assumptions about layout and styling
- Designed for teams building custom component systems
Both libraries aim to solve similar problems—but they make very different trade-offs in terms of abstraction, control, and developer freedom.
What this blog covers (and why)
If you’re a developer choosing between Radix UI and Base UI, the real question usually isn’t “Which is better?”—it’s:
Which one fits my project, team, and long-term goals?
In this blog, we’ll:
- Break down how Radix UI and Base UI differ at a conceptual level
- Compare their APIs, accessibility models, and developer experience
- Highlight real-world decision points instead of surface-level features
- Explain why we chose Base UI for Shadcn Space, based on actual constraints and requirements
By the end, you should have a clear understanding of:
- When Radix UI makes sense
- When Base UI is the better foundation
- Why Base UI aligns better with highly customizable systems like Shadcn Space
What is Radix UI?
Overview and Philosophy
Radix UI is an open-source, headless UI component library for React.
Its main goal is to help developers build accessible and high-quality UI components without having to deal with all the hard accessibility and interaction details themselves.
Radix UI believes that:
- Most UI patterns (like dialogs, dropdowns, tooltips) are already well-defined
- But native HTML components are either missing, limited, or hard to customize
- So developers often rebuild these components incorrectly
Radix UI addresses this by providing well-tested, accessible primitives that serve as the foundation of your design system.
Key Features
Radix UI focuses on making developers’ lives easier.
Accessible by default
- Handles ARIA attributes
- Manages focus automatically
- Supports keyboard navigation
- Follows WAI-ARIA guidelines
Unstyled
- No CSS included
- You control all styling
- Works well with Tailwind CSS
Open and customizable
- Components are split into parts (like Trigger, Content)
- You can wrap components
- You can add your own props, events, or refs
Uncontrolled by default
- You don’t need to manage state manually
- But you can control the state if needed
Great developer experience
- Fully typed TypeScript APIs
- Consistent patterns across components
- asChild prop lets you control the rendered HTML element
Supported Components
Radix UI provides many commonly used UI primitives, including:
- Dialog / Modal
- Dropdown Menu
- Tooltip
- Popover
- Accordion
- Tabs
- Slider
- Checkbox
- Select
- And more …
These components cover the majority of UI needs for typical web applications.
Accessibility Approach
Accessibility is the core strength of Radix UI.
Radix UI:
- Follows WAI-ARIA design patterns
- Handles focus traps (e.g., inside dialogs)
- Supports keyboard interactions like Esc, Tab, and arrow keys
- Works well with screen readers
This means developers can build accessible UIs without deep accessibility knowledge.
The trade-off is that accessibility logic is closely tied to Radix’s component structure, which can sometimes limit custom layouts.
Typical Use Cases
Radix UI is a great fit when:
- You want accessible components quickly
- Your UI uses common patterns
- You’re building dashboards or SaaS apps
- You want stable, production-ready primitives
- You’re using shadcn/ui or Tailwind CSS
What is Base UI?
Overview and Philosophy
Base UI is a headless UI library focused on flexibility and control.
While Radix UI gives you ready-made primitives, Base UI gives you behavioral building blocks that you assemble yourself.
Base UI’s philosophy is:
Accessibility first, structure last.
It provides the logic needed for accessible interactions—but leaves markup, layout, and styling entirely up to the developer.
Key Features
Base UI focuses on control and customization.
Accessibility built in
- ARIA attributes
- Role attributes
- Keyboard navigation
- Focus management
- Pointer interactions
Low-level primitives
- No predefined layouts
- No forced component structure
- You decide how components are built
Flexible APIs
- Props like initialFocus and finalFocus
- Easy to integrate into custom systems
Tested across environments
- Browsers
- Devices
- Screen readers
- Platforms
Component Architecture
Base UI components are meant to be composed, not consumed directly.
Instead of importing a full component, you:
- Attach Base UI behavior to your own components
- Decide where the state lives
- Control the DOM structure completely
Example (conceptually):
- Radix UI → “Here is a Dialog structure.”
- Base UI → “Here is dialog behavior — apply it how you want”
This makes Base UI ideal for building custom design systems.
Accessibility Model
Accessibility is a top priority in Base UI, but with more developer responsibility.
Base UI:
- Handles keyboard navigation (Arrow keys, Enter, Esc, etc.)
- Manages focus automatically
- Provides tools for accessible labels and forms
Developers are responsible for:
- Styling focus states (:focus, :focus-visible)
- Ensuring good color contrast
- Providing accessible names where needed
This gives flexibility, but requires more awareness from developers.
Typical Use Cases
Base UI works best when:
- You are building a component registry platform
- You provide ready-to-copy code blocks
- You ship animated and interactive components
- Users are expected to customize markup and styles
- Flexibility matters more than predefined structures
In these kinds of platforms, components need to adapt to many design systems and styling setups. Base UI makes this easier by providing behavior and accessibility without forcing a fixed structure.
Radix UI vs Base UI: Core Differences (with code)
Design Philosophy
Radix UI gives you a predefined structure that already follows best practices.
Base UI gives you behavior only, and you decide the structure.
This difference becomes very clear in code.
Component Abstraction Level
Radix UI (Structured Components)
import * as Dialog from "@radix-ui/react-dialog";
function RadixDialog() {
return (
<Dialog.Root>
<Dialog.Trigger>Open</Dialog.Trigger>
<Dialog.Portal>
<Dialog.Overlay className="overlay" />
<Dialog.Content className="content">
<Dialog.Title>Dialog title</Dialog.Title>
<Dialog.Description>
Dialog description
</Dialog.Description>
<Dialog.Close>Close</Dialog.Close>
</Dialog.Content>
</Dialog.Portal>
</Dialog.Root>
);
}You:
- Follow Radix’s component tree
- Style the provided parts
- Get correct behavior automatically
Base UI (Behavior-First)
import { Dialog } from "@base-ui-components/react/dialog";
function BaseDialog() {
return (
<Dialog.Root>
<Dialog.Trigger>Open</Dialog.Trigger>
<Dialog.Popup className="content">
<h2>Dialog title</h2>
<p>Dialog description</p>
<button>Close</button>
</Dialog.Popup>
</Dialog.Root>
);
}You:
- Decide what elements to use
- Decide layout and structure
- Attach dialog behavior to your own markup
Styling Flexibility
Radix UI
- Styling is flexible
- Structure is fixed
- You style around Overlay, Content, etc.
Base UI
- No required layout
- No required element types
- Easier to match custom designs
Example difference:
Radix:
<Dialog.Content className="rounded-lg shadow-lg" />Base UI:
<Dialog.Popup className="grid gap-4 rounded-xl shadow-lg" />With Base UI, you’re not constrained by predefined pieces.
Customization Control
Radix UI
- Customization through props
- Big changes may require workarounds
Base UI
- Full control from day one
- No need to “fight” the library
Example scenario:
If you want to place the close button outside the dialog content:
- Radix UI → harder
- Base UI → trivial
Accessibility Defaults
Radix UI
- Accessibility works automatically
- Focus trapping, Esc key, ARIA handled internally
- Very safe defaults
Base UI
- Accessibility logic is provided
- You apply it to your own structure
- More control, more responsibility
Both are accessible — the difference is who controls the structure.
Animation & Transitions
Radix UI
Uses data-state attributes:
[data-state="open"] {
animation: fadeIn 200ms ease;
}Base UI
No animation assumptions — works with anything:
<Dialog.Popup className="animate-scale-in" />Base UI fits better when:
- Animations are complex
- You use motion libraries
- Layout changes dynamically
Bundle Size and Performance
Radix UI
- Tree-shakeable
- Install only what you need
- Slightly more code due to built-in structure
Base UI
- Smaller primitives
- Minimal overhead
- Ideal for shared component libraries
In real apps, both perform well.
Learning Curve
Radix UI
- Easier to start
- Clear mental model
- Faster initial setup
Base UI
- Takes longer to learn
- Requires system-level thinking
- Pays off as complexity grows
Developer Experience Comparison
Developer experience (DX) is not just about documentation or TypeScript types — it’s about how much friction you feel while building and maintaining UI.
Let’s break that down.
API Design
Radix UI
- APIs are consistent across components
- Components follow a predictable pattern (Root, Trigger, Content)
- Easy to remember once you learn one component
Example mindset:
“If you know how Dialog works, you already know how Dropdown or Tooltip works.”
Base UI
- APIs are more flexible and less opinionated
- Fewer assumptions about how components should be structured
- Feels closer to working with hooks and primitives
Example mindset:
“I get the tools, and I decide how to use them.”
Composition Patterns
Radix UI
- Encourages composition through predefined slots
- Composition works well for standard layouts
- Less flexible for uncommon structures
<Dialog.Root>
<Dialog.Trigger />
<Dialog.Content />
</Dialog.Root>Base UI
- Encourages composition through your own components
- Works well for custom layouts and reusable blocks
- No required component tree
<Dialog.Root>
<CustomHeader />
<CustomContent />
</Dialog.Root>Base UI gives more freedom in how components are composed together.
Controlled vs Uncontrolled Components
Radix UI
- Uncontrolled by default
- Can be controlled when needed
- Works well for most app-level use cases
<Dialog.Root open={open} onOpenChange={setOpen}>Base UI
- State control is explicit
- Easier to integrate with a global or shared state
- Better for complex logic
<Dialog.Root open={isOpen} onOpenChange={setIsOpen}>Both support controlled and uncontrolled patterns, but Base UI often feels more natural when building systems.
TypeScript Support
Radix UI
- Excellent TypeScript support
- Fully typed APIs
- Very reliable autocomplete and error checking
Base UI
- Strong TypeScript support
- Types are flexible to support custom composition
- Slightly more responsibility on the developer
For most teams, both libraries offer a solid TypeScript experience.
Integration with Tailwind & shadcn-style systems
Radix UI
- Works extremely well with Tailwind CSS
- Great fit for shadcn-style components
- Structure aligns with copy-paste component patterns
Base UI
- Ideal for building component registries
- Easier to expose raw markup and logic
- Better for animated and customizable code blocks
If your goal is to provide highly customizable components that users adapt to their own projects, Base UI fits more naturally.
Developer Experience Summary
| Area | Radix UI | Base UI |
| Composition | Slot-based | Free-form |
| State Control | Easy defaults | Explicit control |
| TypeScript | Excellent | Excellent |
| API Style | Consistent & structured | Flexible & low-level |
| Best Fit | App development | Design systems & registries |
When to choose Radix UI
Radix UI works best when you want strong defaults, predictable behavior, and ready-made accessibility without spending time designing your own component logic.
Ideal Project Scenarios
You should strongly consider Radix UI if:
- You want accessible components out of the box
Radix handles keyboard navigation, focus management, and ARIA roles for you. You don’t need to be an accessibility expert to build correct components. - You are building a product UI, not a UI system
For dashboards, admin panels, SaaS apps, and internal tools, Radix helps you move fast. - You want proven, production-tested primitives
Radix has been used in many real-world projects and edge cases are already handled. - Your team prefers clear, stable APIs
The component APIs are consistent and unlikely to change suddenly. - You plan to pair it with Tailwind or shadcn-style components
Radix works very well as the “logic layer” behind styled components.
Example projects:
- SaaS dashboards
- Admin panels
- Internal tools
- MVPs and startup products
- Design systems that prioritize stability
Pros and Cons Summary
Pros
- Excellent accessibility by default
- Stable and well-documented APIs
- Wide community adoption
- Works perfectly with Tailwind and shadcn-style setups
- Less decision-making required
Cons
- Less flexibility at very low levels
- Harder to change internal behaviors
- Animation control is more limited
- Not ideal for building highly custom UI frameworks or registries
In simple terms
If your goal is to build a product quickly and safely, Radix UI is usually the better choice.
It gives you:
“Good defaults, fewer decisions, and fewer bugs.”
When to choose Base UI
Base UI isn’t trying to be the best choice for every project.
It shines when flexibility, control, and customization matter more than ready-made behavior.
Ideal Project Scenarios
Choose Base UI if you are building:
1. Component Registry Platforms
Platforms like Shadcn Space that:
- Provide copy-pasteable UI components
- Share full component code, not just APIs
- Expect developers to edit structure, logic, and styles
- Offer animated components and layout blocks
Base UI works great because it does not hide logic behind heavy abstractions.
2. Websites that use UI blocks from multiple registries
This is a big one
If your website:
- Uses UI blocks from different registries
- Copies components from open-source libraries
- Mixes layouts, sections, and interactions
- Needs to adapt third-party code quickly
Base UI lets you fully control the copied code without fighting the library.
You’re not locked into:
- Strict component APIs
- Hidden internal logic
- Opinionated structure
Instead, you get plain, understandable React code.
3. Design systems with heavy customization
Best when:
- Your design system changes often
- You customize markup and behavior per project
- You want consistent patterns, not rigid components
Base UI gives you the freedom to reshape components as your system evolves.
4. Animation-First Interfaces
Perfect if:
- Animations are part of the brand identity
- You use Framer Motion or CSS animations
- You need full control over transitions and timing
Base UI keeps animations outside the component logic, where they belong.
5. Teams that want ownership over code
Great for teams that:
- Want to understand every line of UI code
- Prefer composition over configuration
- Don’t want vendor lock-in
- Value long-term maintainability
In one line
If your product consumes UI blocks from registries and needs full control,
Base UI is the better foundation.
Pros and Cons Summary
Pros of Base UI
- Highly flexible architecture
- Easy to customize and extend
- Great for copy-paste and registry use
- Animation-friendly
- No forced styling or structure
- Accessible foundations included
Cons of Base UI
- Requires more setup than Radix UI
- Less “plug-and-play” behavior
- Smaller ecosystem compared to Radix
- Developers must handle styling carefully
- Not ideal for quick app scaffolding
Why we choose Base UI for Shadcn Space
At Shadcn Space, our priority is simple:
Developers should be able to copy a component and use it freely.
The technology we choose should never limit what you can do with the code.
That principle is why we built Shadcn Space on Base UI.
Our Requirements
When you copy a block from Shadcn Space, you should be able to:
- Paste it into any React and Next.Js projects
- Use it without installing a UI library
- Modify the structure and logic freely
- Add or remove animations easily
- Refactor or delete parts without breaking anything
- Avoid long-term dependency lock-in
In other words:
The code should work for you, not against you.
Why dependency-light code is better for developers
Many developers use UI registries to:
- Learn patterns
- Move fast
- Customize heavily
- Mix components from different sources
Heavy dependencies make this harder:
- You must install extra packages
- You must learn library-specific APIs
- Removing or changing the library later becomes risky
That’s not ideal when the goal is reusable, adaptable code.
How Base UI helps developers
Base UI allows us to share components that are:
- Simple and explicit
- Easy to understand
- Easy to modify
- Easy to replace or remove
- Not tied to a strict component API
So when you use a block from Shadcn Space:
- You are not “adopting Base UI.”
- You are just using good React code
- You stay in full control
This makes components safer to use in:
- Existing codebases
- Large teams
- Long-lived projects
Why this matters Long-Term
Projects evolve.
Requirements change.
Designs get redesigned.
Because Shadcn Space components are built with Base UI:
- You won’t be stuck with a dependency you don’t want
- You can refactor at your own pace
- You can adapt components to new patterns
- You can keep your codebase clean
That flexibility benefits you, not us.
The Core Reason
We chose Base UI so developers don’t feel locked in.
It helps us deliver:
- Shareable code
- Editable components
- Future-proof blocks
- Developer-owned UI
That’s what Shadcn Space is about.
Shadcn Space uses Base UI so developers can copy, modify, and own the code — without constraints.
Conclusion
Radix UI and Base UI are both solid choices, but they serve different goals.
Radix UI works best when you want to build applications quickly with strong accessibility and stable APIs.
Base UI works better when you want to share UI code, modify it freely, and avoid dependency lock-in.
That’s why Shadcn Space uses Base UI — so developers can copy any block, change it however they want, and use it in their own projects without constraints.
If you’re already using Radix UI, we also provide a step-by-step migration guide to help you move from Radix UI to Base UI smoothly:
Migration guide: https://shadcnspace.com/docs/getting-started/migrate-to-baseui
Choose the tool that matches how you work.