This guide covers what design system components are, why they matter, how serious organizations build and maintain them, and which component libraries are worth your attention. We'll also get into some lesser-known libraries that deserve more credit, answer the questions people actually search for, and give you a practical starting point for building your own.

What is a design system component?

A design system component is a reusable, self-contained UI element that bundles visual design and functional behavior together. Think of it like a LEGO brick: simple on its own, but combinable into something much bigger.

Design system components typically include:

• Visual specifications: colors, typography, spacing, and iconography

• Interaction states: default, hover, focus, active, disabled

• Accessibility guidelines: ARIA roles, keyboard navigation, screen reader support

• Code implementations: HTML/CSS, React, Vue, Angular, or Web Components

• Usage documentation: when to use it, when not to, and common pitfalls

A real design system component isn't just a styled div. It's a contract between designers and developers, a promise that this thing will look and behave the same way everywhere it appears.

What are the 7 basic elements of design?

Before getting into specific components, it's worth knowing what all visual design actually builds from. The seven basic elements are:

1. Line: guides the eye and defines boundaries

2. Shape: geometric or organic forms that create structure

3. Color: evokes emotion and establishes hierarchy

4. Typography: communicates tone and readability

5. Texture: adds depth and tactile feel to digital surfaces

6. Space: negative and positive space create balance and focus

7. Value: lightness and darkness create contrast and emphasis

Every design system component traces back to these. Your color tokens, typographic scales, spacing systems, iconography choices, all of it. Understanding the fundamentals means your component library is visually coherent, not just technically functional.

What are the important components of system design?

When people ask about important components of a UI/UX design system, they're usually talking about these categories:

Foundational tokens

Design tokens are the atomic values components consume: colors, spacing, font sizes, border radii, shadows, and motion curves. They're the DNA of your system. Get these wrong and nothing else will hold together.

Typography components

Headings, body text, captions, labels, and links form the backbone of content hierarchy. A good typography system defines scales, weights, and line heights that work across breakpoints without falling apart.

Form elements

Input fields, checkboxes, radio buttons, toggles, selects, and date pickers are some of the most-used and least-forgiven components in any product. Validation states, error messages, and accessibility can't be afterthoughts here.

Navigation patterns

Menus, breadcrumbs, tabs, pagination, and sidebars move users through your product. Consistent navigation reduces cognitive load and genuinely improves task completion rates.

Feedback and status components

Toasts, alerts, badges, progress bars, and loading spinners tell users what's happening. These get overlooked constantly, and that's a mistake. They're what users see when something goes wrong, so they matter more than most people realize.

Data display

Tables, charts, cards, lists, and timelines present structured information. These components live in the tension between information density and clarity, and getting that balance right is harder than it looks.

Overlay components

Modals, drawers, tooltips, and popovers surface contextual information without breaking the main flow. Animation, focus trapping, and dismissal behavior all need careful thought. This is where a lot of accessibility bugs live.

What are the 7 golden rules of UI?

Ben Shneiderman's eight golden rules (often condensed to seven in practice) hold up well as a checklist for every component you build:

1. Strive for consistency: same terminology, actions, and visual patterns throughout

2. Enable shortcuts for frequent users: keyboard shortcuts, quick actions, and progressive disclosure

3. Offer informative feedback: every interaction should confirm what happened

4. Design dialogs to yield closure: group actions into sequences with a clear beginning, middle, and end

5. Offer simple error handling: prevent errors where possible; when they happen, make recovery obvious

6. Permit easy reversal of actions: undo, cancel, and back reduce anxiety and encourage exploration

7. Support internal locus of control: users should feel in control, not manipulated

These principles matter most in form elements, modals, and data manipulation interfaces, which happen to be where most products have their worst UX problems.

The anatomy of a great design system

A mature design system is more than a pile of components. It's an ecosystem that includes:

• A component library: the visual and coded implementations

• A design token system: the source of truth for all visual decisions

• A documentation site: guidelines, examples, and do/don't patterns

• A governance model: who owns the system, how contributions work, how versioning happens

• Figma/Sketch libraries: design files that mirror the production codebase

• Accessibility standards: WCAG compliance targets and testing procedures

98.css: nostalgia meets modern web standards

98.css is a retro component library that recreates the Windows 98 aesthetic using pure CSS. Created by Jordan Scales, it's part love letter to the early web, part surprisingly useful teaching tool for understanding how visual components can be built with minimal CSS.

The novelty is obvious, but 98.css also demonstrates real design system principles: consistent visual language, semantic HTML support, and zero JavaScript dependencies. Sometimes the most memorable results come from constraint, not complexity. The library includes Windows 98-style buttons, title bars, input fields, progress bars, and dialog boxes, all built with standard HTML elements and class names.

a11y Style Guide: accessibility-first design system components

The a11y Style Guide is built with accessibility as its primary principle, not something bolted on at the end. It gives designers and developers WCAG-compliant components covering form elements, navigation patterns, multimedia, and rich text.

What makes it genuinely useful is the explicit documentation alongside each component: ARIA roles, keyboard interaction models, color contrast ratios. It bridges the gap between design intent and technical implementation. For teams building products that need to meet Section 508 or EN 301 549 standards, it's an invaluable reference.

Ant Design: enterprise-grade design system components

Ant Design is one of the most widely used React component libraries in the world, developed by Alibaba's Ant Group. It powers thousands of enterprise applications in finance, e-commerce, and SaaS globally.

The library has over 60 high-quality UI components, from basic inputs and buttons to complex data tables, tree selectors, and virtual scrolling lists. The design language covers color semantics, typographic scales, spacing systems, and motion curves. Tokens are highly configurable, so teams can create branded themes while keeping components consistent. Ant Design 5.0 introduced a CSS-in-JS theming engine and a new token architecture, which made it considerably more flexible for modern React apps.

Ariakit: headless accessible design system components

Ariakit (formerly Reakit) takes a different approach: fully accessible, unstyled UI primitives for React. Rather than handing you pre-styled components, it gives you the behavioral and accessibility logic while leaving visual decisions entirely to your team.

This is ideal for teams building bespoke design systems who need solid accessibility foundations without inheriting someone else's visual opinions. Ariakit handles focus management, keyboard navigation, ARIA attribute management, and portal rendering automatically. Components include Dialog, Menu, Tooltip, Combobox, Select, Tab, and more, each following WAI-ARIA Authoring Practices Guide patterns precisely.

Atlassian Design System: scalability at enterprise scale

The Atlassian Design System runs Jira, Confluence, Trello, Bitbucket, and dozens of other products used by millions of professionals. It's one of the most well-documented design systems anywhere, and worth studying if you're serious about building components at scale.

The component library is built in React and covers everything from atomic elements like Avatar, Badge, and Button to complex patterns like Inline Edit, Multi-Select, and Tree. Atlassian's token system supports light and dark modes, high contrast accessibility modes, and custom brand themes, all through a single semantic token layer. The component API design is rigorous, and the migration guides are unusually thorough. Most enterprise teams could learn something from how they handle this.

Auro: Alaska Airlines' design system

Auro is Alaska Airlines' open-source design system, built on Web Components standards rather than any specific framework. The choice is deliberate: Web Components work across React, Vue, Angular, or plain HTML without rewriting the library for each.

The component set covers travel and commerce interfaces: date pickers, flight status indicators, form components, alerts, and more. The use of Custom Elements, Shadow DOM, and CSS Custom Properties shows how modern web standards can power production-grade components without framework lock-in. If your organization runs a multi-framework tech stack, Auro's architecture is worth a close look.

Aurora: Government of Canada design system

Aurora is the Government of Canada's design system, built to create consistent digital experiences across federal web properties. It has to work for an unusually wide audience: elderly Canadians using assistive technology, mobile users in rural areas with limited bandwidth, and everyone in between.

Aurora's components include bilingual support (English and French), WCAG 2.1 AA accessibility, and performance-optimized implementations. It also covers government-specific patterns like service availability indicators, authentication flows, and official announcement banners. For anyone designing public-sector products where accessibility compliance isn't optional, Aurora is a useful reference.

Backpack: Skyscanner's travel design system

Backpack is Skyscanner's open-source design system, built specifically for travel and search interfaces. What makes it stand out is the multi-platform approach: component implementations exist for React, React Native, iOS (Swift), and Android (Kotlin), so visual and behavioral consistency holds across web and native mobile.

The component library includes travel-specific patterns like date range pickers, price indicators, map overlays, and star ratings alongside standard UI primitives. A single source of truth for design tokens compiles to platform-specific formats, which eliminates the visual drift that usually creeps in between web and native. For cross-platform teams, Backpack's token architecture is worth studying.

Base Web: Uber's production design system

Base Web is Uber's open-source React component library. It powers Uber's internal tools, driver and rider dashboards, and various consumer-facing web applications. The thing that distinguishes it is the override system: every component exposes a comprehensive set of overrides that let teams customize styling, behavior, and sub-components without forking the library.

That architecture is a real solution to one of the hardest problems in design systems: how do you stay opinionated enough to enforce consistency while staying flexible enough for diverse product needs? Base Web components include Calendar, DataTable, FileUploader, Drawer, and Payment Card, which tells you something about the operational complexity Uber's internal teams deal with. The library uses Styletron for CSS-in-JS and has a TypeScript-first API.

BBC Global Experience Language (GEL): broadcasting-scale design

BBC GEL has been guiding BBC's digital products since 2012, which makes it one of the longest-running design systems around. It defines the visual language, interaction patterns, and accessibility standards for BBC News, BBC Sport, BBC iPlayer, BBC Sounds, and dozens of other properties serving hundreds of millions of users.

GEL's component set is built around the realities of broadcasting and journalism: article layouts, media players, live event indicators, weather displays, and content recommendation carousels. The accessibility standards go beyond WCAG and are informed by actual user research with disabled audiences. The BBC has a public service mandate to be accessible to everyone, and that shows in how the system is built. GEL also provides explicit guidance for TV, mobile, tablet, and desktop, because the BBC's audience genuinely uses all of them.

How to build and maintain design system components

Start with an audit

Before building anything new, look at what you already have. Catalog repeated patterns, visual inconsistencies, and components that exist in three slightly different versions across your product. That audit becomes your roadmap and prevents you from building things that already exist in some form.

Define your token architecture

Set up your design token hierarchy before touching any component. Global tokens (brand colors, base font sizes) feed semantic tokens (primary button background, error text color), which feed component tokens (button-primary-bg, input-error-border-color). This three-tier structure means you can theme and update components systematically rather than hunting through CSS files.

Prioritize accessibility from day one

Retrofitting accessibility into components after the fact is painful and expensive. Build ARIA patterns, focus management, keyboard navigation, and color contrast compliance into your specifications from the start. Use axe-core, Storybook's a11y addon, and actual screen reader testing to validate components before release.

Document thoroughly

The best component in the world is useless if nobody knows how to use it correctly. Write clear usage guidelines, document all props and variants, provide interactive examples, and be explicit about when not to use each component. Documentation isn't optional extra work. It's part of the component.

Establish a governance model

Decide how contributions get proposed, reviewed, and merged. A federated model, where multiple teams contribute and a core team reviews, works well for large organizations. A centralized model, where a dedicated systems team builds everything, works better for smaller companies. Whichever you pick, write it down and tell everyone.

Version and communicate changes

Use semantic versioning for your component library. Communicate breaking changes, deprecations, and migration paths clearly in release notes. For major API changes, consider providing codemods to reduce the burden on consuming teams.

The future of design system components

A few trends are genuinely changing how teams build and consume components:

• AI-assisted component generation: tools like GitHub Copilot, v0 by Vercel, and Figma's AI features can generate component code from designs, which is already speeding up development cycles in real ways.

• Tokenized theming at scale: the W3C Design Tokens Community Group spec is moving toward standardized token formats that work across Figma, Style Dictionary, CSS, and other tools.

• Figma Variables and Dev Mode: tighter integration between design files and production code is shrinking the translation layer between design and development.

• Universal design systems: Web Components and cross-framework standards are making write-once, use-anywhere component libraries more viable.

• Accessibility automation: automated accessibility testing is being embedded directly into CI/CD pipelines, which turns accessibility from a final check into a baseline requirement.

Choosing the right design system components for your team

With this many libraries available, the choice can feel paralyzing. A few things worth checking:

• Framework alignment: does it support your tech stack?

• Accessibility maturity: does it meet WCAG 2.1 AA out of the box?

• Customization depth: can you theme and extend components without forking?

• Maintenance and community: is it actively maintained, and is the community helpful?

• Documentation quality: are there real examples, API references, and usage guidelines?

• Bundle size: do components tree-shake well?

There's no universally best library. The right choice depends on your product's scale, your team's technical preferences, your audience's accessibility needs, and your design language goals. Anyone who tells you otherwise is selling something.

Wrapping up

Design system components are where consistency and speed actually come from in product development. From design tokens and typography scales to data tables and overlay systems, every component is an investment that compounds over time. The libraries covered here, from 98.css to Atlassian, from a11y Style Guide to BBC GEL, each have something worth learning from, whether you adopt them or just study how they made their decisions.

The principles don't change much regardless of what you're building: start with clear tokens, bake accessibility in from the beginning, document everything, and govern your system with clear processes. Teams that do this consistently ship faster, onboard new members more easily, and spend less money fixing things later.

If you haven't started yet, start now. You'll wish you had started sooner, but that's true of everyone.

Frequently asked questions about design system components

What is a design system component?

A design system component is a reusable, self-contained UI building block that packages visual design specifications, interaction states, accessibility requirements, and code implementation together. Examples include buttons, form inputs, modals, navigation menus, and data tables. They get used across a product or suite of products to keep visual and behavioral patterns consistent.

What are the 7 basic elements of design?

Line, shape, color, typography, texture, space, and value (lightness/darkness). These underpin every visual design decision in a system, from color token selection and typographic scales to spacing and iconography.

What are the important components of system design?

For a UI design system: design tokens (colors, spacing, typography), foundational components (buttons, inputs, icons), navigation patterns, feedback and status components (alerts, toasts, progress indicators), data display components (tables, cards, charts), overlay components (modals, drawers, tooltips), and documentation. Governance models and accessibility standards are equally important, even though they're not visual.

What are the 7 golden rules of UI?

Based on Shneiderman's principles: strive for consistency, enable shortcuts for frequent users, offer informative feedback, design dialogs to yield closure, offer simple error handling, permit easy reversal of actions, and support the user's internal locus of control. These should be baked into every component's specification, not treated as nice-to-haves.

How many components should a design system have?

There's no fixed number. Small teams might start with 20 to 30 core components. Enterprise systems like Atlassian or Material Design have 60 to 100+. Fewer components that are well-documented and thoroughly accessible will serve you better than many components that are half-finished. Grow based on real product needs, not imagined future requirements.

What is the difference between a design system and a component library?

A component library is the set of reusable coded UI elements. A design system is broader: it includes the component library plus design tokens, usage guidelines, design principles, accessibility standards, governance processes, Figma libraries, and the team and tooling that maintain all of it. The component library is one artifact inside the design system.

Should I build a custom design system or use an existing library?

For most teams, adopting and customizing an established library like Ant Design, Material Design, or Atlassian is more efficient than building from scratch. Custom makes sense if your brand requirements are highly distinctive, your product has specialized needs no existing library covers, or you have the team capacity to maintain it long-term. A common middle path: use a headless library like Ariakit or Radix UI for accessible behavior and build a custom visual layer on top.