Headless UI Libraries for SvelteKit + Tailwind (2025)

Introduction

When developing applications with SvelteKit, you often face the dilemma: you want accessible, beautiful UI components but also want to retain freedom over design. Headless UI libraries are powerful in exactly these situations.

This article thoroughly compares the major Headless UI libraries available for SvelteKit + Tailwind environments and explains how to choose the best one for your project requirements. It delivers practical, work-ready content from installation steps to caveats and operational tips.

What you'll learn in this article: - Features and differences of four major Headless UI libraries - A selection flowchart based on project requirements - Implementation caveats and best practices - SSR support and accessibility considerations

What is a Headless UI library?

A Headless UI library provides logic and accessibility features while leaving styling up to the developer. Unlike conventional UI libraries, the appearance is not predetermined, so you can build your own design system while delegating complex interactions and accessibility requirements to the library.

Four major SvelteKit-compatible libraries

1. Melt UI — The pinnacle of the Builder API

Official site: https://www.melt-ui.com/
GitHub: https://github.com/melt-ui/melt-ui

Melt UI provides the lowest-level API among Svelte Headless UI libraries. It adopts the Builder API pattern and gives developers maximum control.

// Melt UI Builder API example
import { createCollapsible, melt } from '@melt-ui/svelte'

const { 
  elements: { root, content, trigger }, 
  states: { open } 
} = createCollapsible()

Features: - Accessibility implementation compliant with WAI-ARIA - Highly flexible and supports any customization - Full TypeScript support - SSR/SvelteKit compatible

Use cases: - When you need advanced customization - When you want to build a custom design system - When the team has strong design/architecture skills

Installation:

npm install @melt-ui/svelte

2. Bits UI — A practical, balanced choice

Official site: https://bits-ui.com/
GitHub: https://github.com/huntabyte/bits-ui

Bits UI is built on top of Melt UI but provides a more ergonomic component API. Its design is familiar to developers accustomed to React/Vue.

// Bits UI Component API example
<script>
  let value = null
</script>

<Select.Root bind:value>
  <Select.Trigger>
    <Select.Value placeholder="Select a fruit" />
  </Select.Trigger>
  <Select.Content>
    {#each fruits as fruit}
      <Select.Item value={fruit.value}>
        <Select.ItemIndicator />
        <Select.ItemText>{fruit.label}</Select.ItemText>
      </Select.Item>
    {/each}
  </Select.Content>
</Select.Root>

Features: - Balances Melt UI's stability with easy-to-use components - Rich component library - Based on shadcn-svelte - Low learning curve

Use cases: - When you want a balanced solution - When you want consistency in team development - When many team members have React/Vue experience

Installation:

npm install bits-ui

3. Svelte Headless UI — A bridge for migrations

Official site: https://svelte-headlessui.goss.io/
GitHub: https://github.com/rgossiaux/svelte-headlessui

A community project that ports Headless UI libraries from React/Vue to Svelte. It offers an API familiar to those with existing Headless UI experience.

Features: - Community implementation (not an official Tailwind Labs project) - Provides about 10 core components (Dialog, Menu, Popover, etc.) - High affinity with Tailwind UI patterns - Useful when migrating from React/Vue to Svelte

Caveats: - Limited number of components - Tailwind UI samples may need adjustments rather than being usable as-is

Use cases: - Developers experienced with React/Vue Headless UI - When you want to leverage Tailwind UI - When component requirements are limited

Installation:

npm install @rgossiaux/svelte-headlessui

4. shadcn-svelte — A copy-and-paste paradigm

Official site: https://www.shadcn-svelte.com/
GitHub: https://github.com/huntabyte/shadcn-svelte

Unlike traditional libraries, shadcn-svelte generates and copies component code directly into your project.

Features: - Not a library per se; generated code is placed directly in your project - Beautiful designs based on Bits UI + Tailwind - Easy installation via CLI - Extremely high freedom - Updates are typically applied by manually merging generated code

Use cases: - When you want production-quality UI fast - When you want to build a design system - When you can manage maintenance of generated code yourself

Installation:

npx shadcn-svelte@latest init
npx shadcn-svelte@latest add button

Selection flowchart by project requirements

What are your project requirements?
    ↓
Need production-quality UI ASAP → shadcn-svelte
    ↓
Want a balanced solution → Bits UI
    ↓
Need maximum customization freedom → Melt UI
    ↓
Are you familiar with existing Headless UI APIs? → Svelte Headless UI

Feature comparison table

| Item | Melt UI | Bits UI | Svelte Headless UI | shadcn-svelte | |------|---------|---------|-------------------|---------------| | Svelte 5 support | ✅ | ✅ | ⚠️ Partial | ✅ | | SSR support | ✅ | ✅ | ✅ | ✅ | | Number of components | 25+ | 30+ | ~10 | 40+ | | Learning cost | High | Medium | Medium | Low | | Customizability | Highest | High | Medium | High | | TypeScript support | Full | Full | Full | Full | | Positioning | floating-ui | floating-ui | Custom | floating-ui | | Updates | npm | npm | npm | Manual | | Maintenance | Active | Active | Individual | Active |

Frequently Asked Questions (FAQ)

Q: What is the difference between Melt UI and Bits UI? A: Melt UI provides a low-level Builder API, while Bits UI wraps that with a Component API. Bits UI has a lower learning curve; Melt UI offers superior customizability.

Q: Can I use shadcn-svelte in commercial projects? A: Yes. It is provided under the MIT license and can be used commercially. However, generated code becomes part of your project, so maintenance is your responsibility.

Q: What should I be careful about when using Svelte 5? A: Melt UI and Bits UI support Svelte 5 runes (e.g., $state, $derived), but Svelte Headless UI may have incomplete support in some areas. Check the compatibility of each library with your Svelte version before starting the project.

Q: Any caveats when using Dialog/Popover with SSR? A: - Generate only the closed-state HTML on the server - Control initial styles using data-state="closed" - Enable portal functionality after client-side hydration completes - Handle layout shift when scroll lock is used (adjust body padding)

Accessibility checklist

Dialog component - [ ] Can be closed with the Esc key - [ ] Focus is moved to an appropriate element when opened - [ ] Focus trap works - [ ] Focus returns to the original element when closed - [ ] aria-labelledby and aria-describedby are properly set

Menu/Select components - [ ] Arrow keys navigate between items - [ ] Typeahead (typing to navigate items) works - [ ] Home/End keys move to first/last item - [ ] Appropriate ARIA roles (e.g., menu, menuitem) are set - [ ] Screen readers announce properly

Common checklist items - [ ] Respect prefers-reduced-motion for animations - [ ] Fully operable with keyboard only - [ ] Do not convey information by color alone - [ ] Ensure sufficient contrast ratios

Practical caveats and best practices

Svelte version compatibility Each library differs in Svelte 4/5 compatibility. Verify support versions before starting the project and keep them aligned.

SSR/SvelteKit considerations Components like Dialog and Popover perform DOM operations and require attention in SSR environments: - Portal functionality and focus traps are enabled client-side - Use appropriate branching for onMount-based logic vs SSR - Minimize layout shift and flicker on initial render

Common implementation pitfalls

Z-index design

/* Specify portal target clearly */
.modal-overlay { z-index: 50; }
.modal-content { z-index: 51; }

Form integration

// Svelte 5 (using runes)
let formData = $state({
  email: '',
  notifications: false
})

// Svelte 4 (legacy style)
import { writable } from 'svelte/store'
const formData = writable({
  email: '',
  notifications: false
})

Animation implementation Headless UI libraries do not include animations. Combine Svelte transitions and Tailwind animation utilities as needed.

Performance and maintainability considerations

Bundle size comparison - Melt UI: Lightweight (import only what you need) - Bits UI: Moderate (Melt UI + wrapper layer) - Svelte Headless UI: Lightweight (limited number of components) - shadcn-svelte: Project-dependent (only the components you use)

Maintenance strategy

Regular update checks - Track library update frequency and history of breaking changes - For shadcn-svelte, manual updates mean you should regularly check diffs

Testing strategy - Use axe-core and Playwright for accessibility tests - Regression tests for keyboard interactions - Verify behavior in SSR environments

Implementation samples

Melt UI Dialog implementation

<script>
  import { createDialog, melt } from '@melt-ui/svelte'

  const {
    elements: { root, trigger, overlay, content, title, description, close },
    states: { open }
  } = createDialog()
</script>

<div use:melt={$root}>
  <button use:melt={$trigger}>Open Dialog</button>

  {#if $open}
    <div use:melt={$overlay} class="fixed inset-0 bg-black/50" />
    <div use:melt={$content} class="fixed inset-0 flex items-center justify-center">
      <div class="bg-white p-6 rounded-lg">
        <h2 use:melt={$title} class="text-lg font-semibold">Dialog Title</h2>
        <p use:melt={$description} class="mt-2 text-gray-600">
          Dialog description goes here.
        </p>
        <button use:melt={$close} class="mt-4 px-4 py-2 bg-blue-500 text-white rounded">
          Close
        </button>
      </div>
    </div>
  {/if}
</div>

Notes: - In SSR environments, apply data-state="closed" as the initial state and control display until hydration completes - Portal target and scroll-lock options can be tuned via library options

Bits UI Select implementation

<script>
  import { Select } from 'bits-ui'

  const fruits = [
    { value: 'apple', label: 'Apple' },
    { value: 'banana', label: 'Banana' },
    { value: 'orange', label: 'Orange' }
  ]

  let value = null
</script>

<Select.Root bind:value>
  <Select.Trigger class="flex items-center justify-between w-48 px-3 py-2 border rounded">
    <Select.Value placeholder="Select a fruit" />
    <Select.Icon class="ml-2" />
  </Select.Trigger>

  <Select.Content class="bg-white border rounded shadow-lg">
    {#each fruits as fruit}
      <Select.Item 
        value={fruit.value} 
        class="px-3 py-2 hover:bg-gray-100 cursor-pointer"
      >
        <Select.ItemIndicator />
        <Select.ItemText>{fruit.label}</Select.ItemText>
      </Select.Item>
    {/each}
  </Select.Content>
</Select.Root>

Notes: Bits UI property names may differ by version (e.g., bind:value vs bind:selected). Check the official docs for the version you use.

Conclusion

Choosing a Headless UI library for SvelteKit + Tailwind depends on project requirements, team skills, and long-term maintenance strategy.

Actionable next steps: 1. Today: Clarify your project requirements and use the selection flowchart to identify the best library 2. This week: Build a quick prototype with the chosen library and evaluate team feedback 3. This month: Before full adoption, verify SSR behavior and run accessibility tests

A suitable library choice can significantly improve development efficiency and user experience. Start with small components and gradually expand the scope of adoption.

References

• Melt UI Documentation: https://www.melt-ui.com/
• Bits UI Documentation: https://bits-ui.com/
• Svelte Headless UI Documentation: https://svelte-headlessui.goss.io/
• shadcn-svelte: https://www.shadcn-svelte.com/
• Tailwind UI: https://tailwindui.com/
• WAI-ARIA Authoring Practices Guide: https://www.w3.org/WAI/ARIA/apg/