Companies Using Radix UI

I read Radix UI detections the way a sales team would, asking what a hit says about the company behind the domain. As of our September 2026 crawl, TechnologyChecker.io detects Radix UI on 608,529 domains, and 326,776 of them match a company record, a 53.7% match rate. The short version: a Radix detection is rarely a standalone choice. It fingerprints one specific way of building React front ends, which makes it more useful for prospecting than its #5 category rank suggests.

What the signal catches

Our rule looks for the CSS custom properties Radix Primitives set for sizing and animation, such as --radix-accordion-content-height and --radix-popover-content-transform-origin, plus the data-radix-collection-item attribute. Those variables sit in stylesheets, so a site that ships shadcn/ui's styles is counted even on a page where no accordion is open. Read the count as domains whose front end is built on Radix Primitives (our technology detection methods post explains how such signals are matched).

A Radix detection is usually a shadcn/ui detection

96.40% of Radix UI domains also run Tailwind CSS and 74.17% run shadcn/ui. Those three usually arrive as one decision. shadcn/ui was built on Radix from its January 2023 launch, styles its components with Tailwind, and copies the component source straight into a project. Our shadcn/ui rule reads a single theme token, so the remaining 25.83% (about 157,000 domains) mixes teams using Radix directly with shadcn/ui themes that renamed that token. We can't separate the two, and I won't guess at the split.

The timing matters. In July 2026, shadcn/ui made Base UI the default for new projects, while stating that Radix is not deprecated and stays fully supported. Base UI comes from the creators of Radix, Material UI and Floating UI. We see Base UI on just 269 of the 608,529 Radix domains, so the change hasn't yet reached the installed base in any visible way.

"A Radix hit tells you less about Radix than about how the site was built: React, Tailwind CSS and, in most cases, shadcn/ui. That combination is the real prospecting signal." - Emma Davies, Data Analyst at TechnologyChecker.io

Sales Signal: Treat Radix as a proxy for a React team working in a Tailwind and shadcn/ui codebase. For design-system tooling, component testing, accessibility auditing or front-end contract work, the Radix filter narrows a broad React list to teams with exactly that codebase shape, and the July 2026 default change is a timely reason to call.

Growth trajectory

Our current crawl window shows 315,231 Radix domains in June 2026, 408,305 in July, 491,208 in August and 608,529 in September. That is close to double in three months, and it isn't an adoption curve. Counts are not a like-for-like series over time: the set of domains we crawl turns over every month, with dead sites dropping out and newly found ones added, and our detection signals widen over time. The steps reflect changes on our side, both the domains we cover and the signals we detect Radix UI with, rather than a surge in adoption.

Exits are easier to count. 57,095 domains have stopped showing the Radix signal since we began tracking it on 16 March 2026, equal to 9.38% of today's base. That is movement observed since we started watching, not a lifetime total.

Sales Signal: Size territories on the September count and ignore the month-over-month slope. A domain that newly appears in our data isn't necessarily a new build, so don't trigger "just adopted" outreach from a first detection alone.

The companies behind the domains

The matched base is small and young. 67.33% of companies with a size band have 1-10 employees and 89.35% have 50 or fewer. Of those with a known founding year, 41.92% were founded in the 2020s and 37.01% in the 2010s. Software Development (7.16%), IT Services (6.21%) and Technology, Information and Internet (6.09%) together make up 19.46%, and Advertising and Marketing Services add another 5.27%. The tail reaches Real Estate (2.84%) and Construction (2.77%), where the agency that built the site may be the real Radix user. The United States leads with 97,501 matched companies, and the United Kingdom, India and Brazil sit within 59 companies of each other behind it.

The enterprise tail is small in share and large in absolute terms: 3,412 companies above 1,000 employees, 723 of them above 10,000. The surface matters more than the logo. In our named list, 33 of 48 companies were detected on a subdomain: developer portals (build.nvidia.com, developer.fiserv.com, dev.st.com), careers sites (jobs.uber.com, mycareer.verizon.com) and ordering flows (order.wendys.com). Nike (www.nike.com) and EA (www.ea.com) are among the 15 detected on the main site. Radix's own case studies page features Linear, Supabase and Vercel, the developer-tool end of this base.

Sales Signal: At an enterprise, route the conversation to the team that owns the detected surface rather than to central IT. A developer portal on Radix points to a developer-facing team, so start there. A careers or ordering site may be run by an outside platform, so confirm who built it before you pitch.

Why this profile has no migration table

We tested where Radix leavers go. We took 51,289 domains that dropped Radix and no longer carried it anywhere, and checked them against Base UI, Headless UI, Chakra, Mantine, Material UI, Bootstrap, Tailwind CSS, shadcn/ui and Next.js. The control failed. shadcn/ui, which ships on Radix, showed 1,814 apparent switchers, level with Material UI's 1,817. Two libraries with opposite relationships to Radix scoring the same says the test is measuring background noise, not switching.

The leavers also look unlike current users. Tailwind CSS was on 37.08% of them against 96.40% of live Radix sites, which points to sites being rebuilt or going offline rather than teams moving to another primitive library. Primitives also coexist freely in one codebase, so there is no exclusive slot to switch.

"When a library built on Radix and a library that competes with it score the same number of switchers, that number is background churn. We would rather publish no migration table than a noisy one." - Emma Davies, Data Analyst at TechnologyChecker.io

Sales Signal: Don't build a "teams leaving Radix" campaign from churn data. A domain that loses the Radix signal is more often a rebuild or a shutdown than a library decision. Start the Base UI conversation with current Radix users instead, since they are the teams the July 2026 default change affects.

Reading the stack for hiring and outreach

Next.js runs on 33.83% of Radix domains and React Router on 33.38%. Use those as your floor for the React share. Our direct React signal reads far lower because modern React builds leave little for it to find, so it undercounts these sites and shouldn't be used to size them. Vercel hosts 21.04%, Amazon Web Services 8.69% and WordPress appears on 5.29%, with Supabase on 1.56%.

The Vue port, radix-vue, set the same --radix- variables until it was renamed Reka UI, which may explain part of the Vue.js share (2.12%). We don't attribute the footprint to AI site builders: Lovable appears on 0.92%, and our Lovable signal is too narrow to settle that question either way.

Sales Signal: For recruiters and staffing firms, a Radix detection on a company site is a concrete skills brief: React (often via Next.js or React Router), Tailwind CSS, shadcn/ui conventions and, for a fifth of the base, Vercel deployment. For developer-tool vendors, the Vercel and Supabase overlaps are the natural integration angles.

How to use this list

Filter Radix UI plus Tailwind CSS to isolate the shadcn-style codebase, then add a company size of 11-200 employees to move past solo builders; the 11-50 and 51-200 bands hold 28.56% of matched companies. Read the detection URL last: a main-domain hit suggests a company-wide front-end choice, a developer portal a platform team.

A workable opener: "I saw [surface] is built on Radix with Tailwind, which usually means a shadcn/ui codebase. shadcn/ui switched new projects to Base UI in July 2026 and still supports Radix. If you're weighing that choice, here is how [product] helps either way."

Build and export the filtered list from all 608,529 Radix UI domains and 326,776 matched companies on TechnologyChecker.io.