Companies Using Babel

Babel does its work before code ships, so almost none of its use shows up on a live page. What a browser can see is the runtime polyfill Babel used to provide, and that is what I counted. As of our October 2026 crawl, TechnologyChecker.io finds it on 379,086 live domains, with 211,242 organisations matched to a company record. Read every number below as a count of sites still shipping an old polyfill, not of teams using Babel today.

What the signal catches

Our rule checks for _babelPolyfill, a global flag set when @babel/polyfill (or babel-polyfill before it) loads. Babel's documentation says the package has been deprecated since Babel 7.4.0 in favour of core-js/stable, and babeljs.io now announces Babel 8.0.0. The code still out there is old. On the 73 company pages where we confirmed the flag in a browser, every one reported core-js 2.x, and 44 reported 2.6.12. Our core-js rule reads the same flag, which is why core-js shows on 100% of these domains.

Who put the polyfill on the page

We took a random sample of 50 live Babel domains and traced the script that set the flag on the 42 pages carrying it. 20 got it from Weebly's own site script, served from editmysite.com. Four Shopify stores got it from shopify-xr, a script Shopify hosts on the store's own domain. Two WordPress sites loaded it through WordPress's bundled wp-polyfill file at version 7.4.4, two BaseKit sites through the builder's runtime, and five through third-party widgets such as a newsletter form and a review badge. Only three served it from their own site's files. The other six were gambling apps on numeric domain names.

The full base shows the same carriers. Weebly runs on 30.86% of the domains in our stack analysis, WordPress on 21.93%, Shopify on 12.62%, BaseKit on 2.86% and Strikingly on 2.17%. Duda, a suspected carrier, covers only 4,056 domains (1.1%). The gambling cluster is harder to size: domains with numeric names or the template title "Welcome" add up to 13,810 (3.8%), and a 400-domain title sample put all gambling apps at 25 (6.25%).

Sales Signal: Remove the platform carriers before you prospect. A Weebly or Shopify domain tells you the platform shipped an old polyfill; it says nothing about the owner's developers.

Growth trajectory

Our current crawl counts 305,348 domains in June 2026, 343,156 in July, 349,374 in August, 359,461 in September and 379,086 in October. 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 37,808-domain step into July reflects changes on our side, both the domains we cover and the signals we detect Babel with, rather than a surge in adoption. Nobody is adopting a package deprecated at 7.4.0.

Exits are easier to read. 91,566 domains have dropped the polyfill on at least one hostname since we began tracking it in March 2026, and when we rechecked on 13 October only 8,814 of 91,673 (9.6%) still ran it on another hostname. A site loses this flag when it rebuilds, changes platform or dies.

"Babel's real footprint is invisible to a crawler. What we can count is the polyfill it stopped recommending, and a third of that sits inside one site builder's runtime." - Mehmet Suleyman, CEO & Co-founder at TechnologyChecker.io

Sales Signal: Treat this as a legacy base that shrinks one rebuild at a time. The 91,566 exits mark sites that changed something; a fresh rebuild is a good moment to sell hosting, analytics or agency work.

The companies behind the domains

69.03% of matched companies with a size band have 1-10 employees and 88.35% have 50 or fewer. Founding years lean older than on the Gutenberg plugin's page: 42.38% in the 2010s and only 12.83% in the 2020s, against 33.14% from the 2020s there. There are 3,121 companies above 1,000 staff, and the named list behaves differently from the random sample. Most large companies load the polyfill from their own bundles: Bank of America's homeloanhelp site, Bosch's PSIRT portal, Novo Nordisk's main site, Deutsche Bank's corporates site and Randstad's theme script. Careers sites are the exception. 37 of the 50 named detections are subdomains, ten are careers sites, and five of those load the identical bundle file. Babel publishes no customer list, so there was nothing vendor-side to cross-check.

Sales Signal: At an enterprise, a polyfill in the company's own bundle points to a web team maintaining an older front end, a fair opening for modernisation or performance work. A careers-site hit points to the HR technology vendor instead.

Industry and geographic concentration

Retail leads at 5.06%, Construction follows at 3.81% and Medical Practices at 2.91%. Software Development, the industry you'd expect for a developer tool, is 2.03%. The United States has 84,316 matched companies, 39.91% of the base, and the United Kingdom 17,131. Germany (9,349), Australia (8,415) and Canada (8,339) are bunched behind. English-speaking countries account for 55.96%, against 46.87% on the Gutenberg plugin's page, which fits the weight of US small-business builders.

Sales Signal: For local-services software, filter Babel plus Weebly plus the US or UK. That isolates small businesses on an older builder whose sites haven't been rebuilt.

Why there is no migration table

We tested switching corridors and published none. A polyfill doesn't get swapped for a rival product; it disappears when a site is rebuilt. The overlaps confirm it. Webpack runs today on 48,233 of the 56,675 domains where we've seen both, Parcel on 3,313 of 4,443, Turbopack on 1,293 of 2,435 and Vite on 276 of 588. Those are tools in the same build chain.

"There's no migration away from a polyfill. It leaves with the old build, usually when a platform ships a new runtime or the owner rebuilds the site." - Mehmet Suleyman, CEO & Co-founder at TechnologyChecker.io

Sales Signal: If you sell build tooling, your buyers are platform vendors such as Weebly and the careers-site providers, not the hundreds of thousands of domains they serve.

Technology ecosystem

Across the 364,858 domains in our stack analysis, jQuery runs on 82.07%, Lodash on 56.42%, Underscore.js on 54.2% and FancyBox on 37.96%. Mustache (32.17%) and Snowplow Analytics (29.26%) ride with Weebly, on 99.7% and 89.3% of its Babel domains. React (8.34%) and Vue.js (8.2%) are thin, and Google Analytics is on 63.94%.

Sales Signal: This is a jQuery-era list. Pitch site rebuilds, performance audits and platform moves; modern framework tooling has little to work with here.

Key takeaways

1. 379,086 live domains still ship Babel's deprecated polyfill; modern Babel builds aren't counted.
2. Weebly carries 30.86% of the base, Shopify 12.62% and WordPress 21.93%.
3. Gambling apps on numeric domains are at least 3.8% of the count.
4. Large companies mostly ship it in their own bundles, except on careers sites.
5. Exits are real: only 9.6% of dropped domains still run it elsewhere.

Sales applications

For targeting, filter Babel on TechnologyChecker.io, remove Weebly, Shopify and WordPress sites, and keep companies with 200+ employees; what remains are teams maintaining their own older front end. For outreach to them, be specific: "Your site still ships @babel/polyfill, which Babel deprecated at 7.4.0. We cut legacy polyfills without a redesign." For competitive work, track the platforms: when Weebly or a careers vendor updates its runtime, thousands of domains will drop off this list together.

The full list of 211,242 matched organisations behind 379,086 Babel polyfill domains, with size, industry and country filters, is on TechnologyChecker.io.