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  • Writer's pictureantoniodellomo

Design Systems vs. Pattern Libraries vs. Style Guides – What’s the Difference?

You’ll often see the terms design system, pattern library, and style guide used interchangeably. The three concepts are connected but definitely not the same.

Let’s clarify definitions, visualize how they fit together, and discuss the major milestones in building a design system.

What is a Design System?

A Design System is essentially an automated atomic design library. It consists of a digital pattern library with predefined and, more importantly reusable, assets: the atoms, molecules and organisms of atomic design. Instead of manually entering the same elements, designers simply ‘pull’ from the library whenever that exact element is needed.

What is a Pattern Library?

Pattern libraries are similar to design systems in many ways. They are repositories of UX and UI elements that frequently appear on a website. Navigation elements, carousels, social media features and more can all be considered part of a pattern library. Once one design creates them, they’re added to the library for everyone to use.

What is a Style Guide?

If a pattern library showcases visual elements, a style guide is the broader documentation. It describes how to use the elements, as well as rules for how the brand should feel, what language to use and how it should work overall. They’re more “instructions” and less “reusable components”.

Illustration of the differences between the parts of a design system and how they fit together. Credits to PEGA Community.

So, how do you use each of these resources effectively?

Use a style guide to learn about the brand and its visual implementation in the UI. A style guide is a prescribed, brand-specific encyclopedia of UI guidelines that will help you better understand the look and feel of a brand – so that you can carry that over when designing your application. For example, a style guide might show you an example of a button, its preferred colors, or shapes.

Use a pattern library to understand how various visual elements can address specific user needs within the application, together. Pattern libraries can help you learn preexisting combinations of design elements so that you don’t need to recreate the wheel when mapping out landing pages, home pages, and more. A pattern library will consistently illustrate where your button appears in modals and illustrate the various page designs in which such a button might appear.

But while a style guide will help you design an on-brand, stylish application, and a pattern library can offer many ideas for combining components according to user needs, it’s the design system that will help you use your components and patterns to focus on your customer’s experience. That’s because it encompasses all the above to present your software as functional, trustworthy, consistent, and beautifully aligned to your company’s brand.

The design system contains a much bigger structural framework to combine how the visual designs work with the underlying technology. It allows you to build your application, while patterns and style libraries tell you about what your application should look like.

Style guides, pattern libraries, and design systems are all important tools for enterprise design. But when it comes to taking your prototype and making it functional, scalable, and user-driven, the robust design system is your best instrument.


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