How many companies use Closure Library?

TechLeads currently detects Closure Library on 58,424 websites. HTTP Archive's monthly crawl, a separate dataset, detected it on 146,932 pages in September 2026.

Who are Closure Library's biggest competitors?

By number of websites, the largest JavaScript libraries technologies besides Closure Library are jQuery (38,650,119), jQuery Migrate (15,265,182), core-js (9,046,687), Swiper (6,535,690), jQuery UI (6,342,235).

Which companies use Closure Library?

Websites using Closure Library include eltiempo.es, phys.org, medicalxpress.com, tvtropes.org, cmjornal.pt, eldiario.es. The full list of 58,424 websites can be exported as a CSV for $29.

Closure Library market share and customers

As of October 8, 2026, Closure Library is used by 58,424 websites in the TechLeads index: 0.04% of all JavaScript libraries detections, the 84th most-used of 357 JavaScript libraries technologies.

58,424

websites using Closure Library

0.04%

share of JavaScript libraries

#84

of 357 in JavaScript libraries

Cite this data

Quoting these numbers? Credit TechLeads with a link to this page.

Citation

TechLeads. "Closure Library Customers and Market Share." Data as of October 8, 2026. https://techleads.fyi/technology/closure-library/market-share

HTML link

<a href="https://techleads.fyi/technology/closure-library/market-share">Closure Library market share (TechLeads data)</a>

Closure Library vs competitors in JavaScript libraries

Websites using each technology in the TechLeads index, and its share of all JavaScript libraries detections.

#	Technology	Websites	Share
1	jQuery	38,650,119	29.7%
2	jQuery Migrate	15,265,182	11.7%
3	core-js	9,046,687	6.9%
4	Swiper	6,535,690	5.0%
5	jQuery UI	6,342,235	4.9%
6	OWL Carousel	3,899,597	3.0%
7	Lodash

Closure Library usage over time

In HTTP Archive's monthly crawl of public websites, Closure Library was detected on 146,932 pages in September 2026, up 45.6% from a year earlier (peak: 243,454). Among the 1,000 most-visited sites, it appeared on 44. HTTP Archive is a separate dataset from the TechLeads index, so its numbers are not added to ours.

Same month, other JavaScript Libraries technologies in HTTP Archive: jQuery 32,400,479, core-js 20,296,277, jQuery Migrate 14,931,388, jQuery UI 10,564,965, Swiper 7,844,933.

Closure Library customers by country

Based on country-code domains (such as .de or .co.uk); websites on .com and other generic domains are not assigned a country.

US478
GB71
FR53
BR40
DE37
IT37
CZ13
GR12
PT12
NL11

Companies using Closure Library

eltiempo.es · Eltiempo.es
phys.org
medicalxpress.com · Medicalxpress
tvtropes.org
cmjornal.pt · Correio da Manh\u00E3
eldiario.es
in.gr · in.gr
tv2.no · TV 2
iq.com · iQIYI
modland.net
sponichi.co.jp · スポニチ Sponichi Annex
ilgiornale.it · il Giornale

See all 58,424 websites using Closure Library or download the full list as a CSV for $29.

How these numbers are calculated

TechLeads scans public websites and detects Closure Library from signals in the page HTML, scripts, cookies, HTTP headers and DNS records. Market share is Closure Library's website count divided by the website counts of all JavaScript libraries technologies we track; a site using two JavaScript libraries tools counts for both. Counts were last refreshed on October 8, 2026 and update daily.

FAQ

Closure Library accounts for 0.04% of JavaScript libraries detections in the TechLeads index (58,424 websites), which makes it the 84th most-used of 357 JavaScript libraries technologies we track.