Design systems used to be a luxury. Big tech had them, everyone else improvised. That changed once teams saw how much time they were wasting rebuilding the same button ten different ways.
Now agencies are building some of the best systems out there. Not just UI kits, but systems tied to code, content, and performance. The kind that make SEO easier and keep paid, email, and social aligned instead of drifting apart.
Let’s get into the ones worth studying in this article.
Shopify Polaris, A System Built For Scale
A lot of agencies build on Shopify, but few really understand Polaris.
Polaris is not just a style guide: it is tied directly to how apps behave, how merchants move through the product, and how developers build. That level of consistency reduces friction in real use, not just in design files.
Some teams treat design systems like mood boards. Polaris shows what happens when the system lives in the product itself. Builds move faster, UX mistakes drop, and handoffs get cleaner.
For ecommerce, this is the bar not because it is perfect, but because it proves the system has to live in code, not Figma.
IBM Carbon, Design With Discipline
IBM built Carbon for a level of scale most teams will never hit, but the lessons carry over.
Carbon is strict. Spacing, type, color, all defined and enforced. That can feel limiting, but it removes a lot of noise. Teams stop debating basics and focus on real problems.
Research from Nielsen Norman Group shows consistent interfaces can improve usability by up to 20% in complex systems. Carbon leans into that idea.
Agencies that borrow from this approach tend to ship stronger platforms that are not necessarily flashier but are easier to use.
Material Design, Still Setting The Baseline
While it is easy to overlook Google’s Material Design, that would be a mistake.
Material changed how teams think about layout, motion, and hierarchy. It also gave designers and developers a shared language, which cuts down confusion fast.
Some agencies avoid it to stand out, but that often backfires. Users already understand these patterns, and ignoring that creates friction.
Material works best when adapted. Good teams know what to keep and what to adjust.
Salesforce Lightning, Built For Real Work
Salesforce built Lightning for one goal: helping people get work done.
It handles dense data, long workflows, and real tasks: not the polished shots you see online, but the messy stuff companies run every day. Agencies working in B2B or SaaS can learn how to structure forms, manage states, and guide users through heavy interfaces.
A system that cannot handle complexity is not a system but decoration.
GOV.UK Design System, Clarity Over Style
The UK Government Digital Service built something most brands struggle with: clarity. Simple is hard. It takes discipline to remove noise without losing meaning. Plain language, simple layouts, accessible components: they’re nothing flashy, only intentional. Guidance from the World Wide Web Consortium shows accessible design improves usability for everyone. This system proves it in practice.
Why Agencies That Build Systems Win
Design systems are not really about design: they are about repeatability. It could mean SEO teams not fighting layout issues. Paid campaigns land on pages that feel consistent. Email and social use the same building blocks.
Teams sometimes build a system, then ignore it. Or they lock it down and stop updating it. Both kill it. A real system evolves. It pulls from analytics, user behavior, and performance data. It feeds back into development and content. It stays alive.
Integration is where the payoff shows. SEO gains from consistent structure and faster pages. Paid traffic converts better when pages feel familiar. Everything connects.
A Quick Reality Check
Some agencies sell “design systems” that are just UI kits with a new label. That is not the same thing. A real system includes code, documentation, and rules people follow. Without that, it breaks the moment deadlines get tight. And they always get tight.
Final Thought
Design systems are not optional if a business wants to scale without chaos. The best web design agencies are not chasing trends. They are building systems that hold everything together, design, SEO, paid, email, all of it. If a redesign is coming, accessibility and structure should be part of the plan from day one. View our list of the best web design services companies that take this seriously tend to build sites that last.