core-js on new websites

JavaScript polyfill library for modern ECMAScript features.

Sites using core-js
3,941
since Aug 2026
Last 30 days
0.2%
of new sites, to Nov 5
+0.2 pts on the 30 days before
Last 7 days
0.7%
of new sites, 7-day average
+0.7 pts on the week before
Rank in Javascript Library
#80
of 1,713 tools, all time
First seen Aug 11, 2026
Last seen Nov 6, 2026
Website github.com

What we found

  1. core-js appeared on about 3,500 new sites in the last 30 days.[1]
  2. Nine in ten new core-js sites also use jQuery.

Share of new sites using core-js

0.00% 0.25% 0.50% 0.75% 1.00% 10 Sep Oct Nov Nov 4, 2026: Detection widened: we now also find this technology inside a site's own scripts. Launches crawled before this date may undercount. [2]

The line is the 7-day average share of new sites that use core-js, since 10 September.

Who uses core-js

Kind of site 954 sites with a known type
TypeSitesShareBar
E-commerce 254 26.6%
Health 204 21.4%
Marketing 85 8.9%
Finance 84 8.8%
Content 75 7.9%
Education 63 6.6%
Games 37 3.9%
Design 34 3.6%
Productivity 33 3.5%
Social 25 2.6%
Developer Tools 20 2.1%
Hiring & HR 15 1.6%
Country[3] 396 sites with a known country
CountrySitesShareBar
US 56 14.1%
France 46 11.6%
Canada 44 11.1%
Spain 34 8.6%
Ukraine 31 7.8%
Brazil 23 5.8%
UK 23 5.8%
India 13 3.3%
Australia 12 3.0%
Germany 10 2.5%
Iran 10 2.5%
Italy 10 2.5%
Domain ending 3,645 sites
EndingSitesShareBar
.com 2,615 71.7%
.uk 108 3.0%
.org 106 2.9%
.net 79 2.2%
.in 75 2.1%
.fr 65 1.8%
.xyz 57 1.6%
.online 55 1.5%
.site 51 1.4%
.store 41 1.1%
.ca 38 1.0%
.ua 37 1.0%

Javascript Library on new sites

# Movement Tool Share of all sites Share of category[4] Bar
1 – jQuery 13.8% 34.3%
2 – jQuery Migrate 7.6% 18.8%
3 – React Router 6.5% 16.1%
4 ▼1 Motion 5.7% 14.1%
5 ▲1 TanStack Router 4.4% 11.0%
6 ▼1 Swiper 3.3% 8.1%
7 ▲1 ES Module Shims 2.9% 7.1%
8 – js-cookie 2.5% 6.1%
9 ▼1 Modernizr 2.3% 5.8%
10 ▲1 GSAP 1.9% 4.7%
11 ▲1 Lenis 1.4% 3.4%
12 ▲3 Three.js 1.3% 3.2%
…
80 ▲159 core-js 0.1% 0.1%

All-time shares across the new sites we track: of all of them, and of the sites using any Javascript Library tool. core-js is typically used alongside jQuery rather than instead of it. Among October launches it ranked #288 in Javascript Library, up from #447 in September. All 1713 in Javascript Library

Often used with core-js

Tool Sites with both vs all new sites Bar
jQuery UI 3,026 688x
Twemoji 2,610 545x
Elementor Pro 1,474 21x
jQuery Migrate 3,105 10x
WordPress 3,352 7.0x

Tools that turn up far more often on core-js sites than on new sites in general, and how many times as common each one is there.

Recently launched products built on core-js

33 of the 3,941 sites using core-js are product launches we list individually. The other 3,908 are new business and personal sites: they count towards the figures above but are not listed here. A watch sends them to you.

Site Found Also detected
TajaBase — Retail, POS & E-commerce Platform tajabase.com · E-commerce Nov 5 Vue.js Hostinger
Dwelln — Real Estate Media Management calientecondo.com Nov 5 React Cloudflare DNS date-fns Fastly
School of Biology – NEET-UG, Nursing & NCLEX MCQs with Explanations schoolofbiology.com · Education · India Nov 5 jQuery Elementor Hello Elementor LiteSpeed Web Server
Home - Madeline Labrador Home madelinelabradorhome.com Nov 5 jQuery Apache Astra Elementor
راصد حضوري | نظام تتبع وتقارير الحضور الذكي rasedhudury.com · Saudi Arabia Nov 5 React Cloudflare Emergent GoDaddy DNS
Tessera AI | Autonomous Physical Security Platform tesserainc.ai · Developer Tools · United States Nov 5 jQuery Cloudflare Dialogs Manager Elementor
Pick It – Pluk frugt og grønt selv, lige i nærheden pickit.one · Productivity Nov 5 jQuery Apache Elementor Google Fonts
Design Tools by Barbi tools-by-barbi.space · Design Nov 5 React Vercel Google Fonts jsPDF
GTMObserver — Automated GTM Deployment & 24/7 GA4 Anomaly Observer gtmobserver.com · Marketing Nov 5 React Clerk Cloudflare Google Fonts
Free Design Brief Generator - GraphicBriefs graphicbriefs.com · Design Nov 5 jQuery Astra cdnjs Elementor
Automatic EPK builder for musicians & labels | Releasr releasewingman.com Nov 5 Next.js React Render Auth.js
UAE Gratuity Calculator khaleejjournal.com Nov 5 jQuery Dialogs Manager Elementor Facebook Pixel

Showing the most recent 12 of 33.

Watches, exports and the API give you all 3,941 sites using core-js, from £15 a month.

Notes

  1. These figures cover websites that went live since April 2026, not the web as a whole.
  2. 4 November 2026: Detection widened: we now also find this technology inside a site's own scripts. Launches crawled before this date may undercount. The dashed line on the chart marks the day.
  3. Country comes from what each site says about itself, such as a company registration, legal terms or a phone number, not just its domain ending. We count a country only where it is stated plainly enough to be sure: a governing-law clause or company registration number on a legal page, a phone country code, or a country domain ending. Sites that publish none are not counted at all.
  4. Some products people expect to see here are filed under a related category: UI Library.

How this page is made

FirstSited looks at each new website near the day it goes live and records what it was built with. We do not go back later, so these figures describe what sites launch with, not what they run today. A site counts towards core-js when we detect core-js on it at that look.

Every share on this page is a proportion of the new sites we were tracking at the time. Sites we found across the wider web count towards the figures, but only product launches are listed by name. How we detect technologies · How we find new sites

Spot a mistake? If a technology shown here is wrong or out of date, email [email protected] and we'll review it.