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Sites built with Proj4js

JavaScript library for transforming coordinates between map projections.

#439 of 1320 in Javascript Library First seen: Jun 10, 2026 Last seen: Sep 22, 2026 Website: proj4js.org
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39 sites

36 found by StackScope, 3 via launch platforms

StackScope Wider Web 22 StackScope Discovery (Indie) 14 Product Hunt 3
  • StackScope Wider Web 22
  • StackScope Discovery (Indie) 14
  • Product Hunt 3
View: All sites All launches Launch platforms StackScope Discovery StackScope Wider Web
Last 7 days 0.0% -0.0pp
Most used with Leaflet, cdnjs, unpkg

Proj4js has been detected on 39 launches we've crawled, with 12 of those in September 2026 (0.0% of the month's launches so far). The 7-day rolling share is 0.0%, roughly steady week on week. Most recent detection: Aqalxy | Plans Topographiques et Calculs Géodésiques au Maroc, 2 days ago.

It's most commonly paired with Leaflet, cdnjs, and unpkg.

Domain endings using Proj4js

39 sites

  • .com 53.85%
  • .app 10.26%
  • .org 7.69%
  • .net 5.13%
  • .site 5.13%
  • .tech 5.13%
  • .br 2.56%
  • .ch 2.56%
  • .online 2.56%
  • .se 2.56%
  • .xyz 2.56%

Share of new sites using Proj4js

Each dot is one launch day. Line is the 7-day rolling average; weekly averages before June 2026. Chart starts at first detection.

0.0%
last 7 days
-0.0pp vs prior week
0.0%
September so far
12 of 1,524,179 sites
39
sites all time
since Jun 2026
Proj4js daily detection trend Before 8 July 2026: launch platforms only. We began crawling the wider web on this date, so the cohort this share is measured against changes here. 5% 2% 0% Jun Jul Aug Sep Jul 1, 2026: Adoption figures now count launches from launch platforms. Use the source view to include StackScope Discovery. Weekly averages before this point, daily after. Jun 26 · 0 / 534 = 0.0% Jun 27 · 0 / 431 = 0.0% Jun 28 · 0 / 382 = 0.0% Jun 29 · 0 / 502 = 0.0% Jun 30 · 0 / 801 = 0.0% Jul 1 · 0 / 795 = 0.0% Jul 2 · 0 / 603 = 0.0% Jul 3 · 0 / 499 = 0.0% Jul 4 · 0 / 411 = 0.0% Jul 5 · 0 / 367 = 0.0% Jul 6 · 0 / 551 = 0.0% Jul 7 · 0 / 1186 = 0.0% Jul 8 · 0 / 12596 = 0.0% Jul 9 · 0 / 23780 = 0.0% Jul 10 · 0 / 22597 = 0.0% Jul 11 · 0 / 16090 = 0.0% Jul 12 · 0 / 20395 = 0.0% Jul 13 · 1 / 21006 = 0.0% Jul 14 · 0 / 20532 = 0.0% Jul 15 · 0 / 17365 = 0.0% Jul 16 · 0 / 14342 = 0.0% Jul 17 · 1 / 19818 = 0.0% Jul 18 · 0 / 22797 = 0.0% Jul 19 · 1 / 26380 = 0.0% Jul 20 · 0 / 22827 = 0.0% Jul 21 · 0 / 21758 = 0.0% Jul 22 · 0 / 23334 = 0.0% Jul 23 · 0 / 16957 = 0.0% Jul 24 · 0 / 12946 = 0.0% Jul 25 · 0 / 8993 = 0.0% Jul 26 · 1 / 20058 = 0.0% Jul 27 · 2 / 33974 = 0.0% Jul 28 · 2 / 38376 = 0.0% Jul 29 · 2 / 50264 = 0.0% Jul 30 · 0 / 44098 = 0.0% Jul 31 · 0 / 51305 = 0.0% Aug 1 · 0 / 50708 = 0.0% Aug 2 · 0 / 49903 = 0.0% Aug 3 · 1 / 48415 = 0.0% Aug 4 · 1 / 37490 = 0.0% Aug 5 · 1 / 32812 = 0.0% Aug 6 · 1 / 36716 = 0.0% Aug 7 · 1 / 37956 = 0.0% Aug 8 · 0 / 39824 = 0.0% Aug 9 · 0 / 34409 = 0.0% Aug 10 · 1 / 29087 = 0.0% Aug 11 · 1 / 32236 = 0.0% Aug 12 · 0 / 33754 = 0.0% Aug 13 · 0 / 50330 = 0.0% Aug 14 · 0 / 51689 = 0.0% Aug 15 · 0 / 51767 = 0.0% Aug 16 · 0 / 52114 = 0.0% Aug 17 · 0 / 41733 = 0.0% Aug 18 · 0 / 54228 = 0.0% Aug 19 · 0 / 49714 = 0.0% Aug 20 · 0 / 67211 = 0.0% Aug 21 · 1 / 90849 = 0.0% Aug 22 · 2 / 91943 = 0.0% Aug 23 · 1 / 91068 = 0.0% Aug 24 · 2 / 79637 = 0.0% Aug 25 · 0 / 69709 = 0.0% Aug 26 · 0 / 65612 = 0.0% Aug 27 · 0 / 84092 = 0.0% Aug 28 · 0 / 84008 = 0.0% Aug 29 · 0 / 84832 = 0.0% Aug 30 · 1 / 93349 = 0.0% Aug 31 · 2 / 91077 = 0.0% Sep 1 · 1 / 92717 = 0.0% Sep 2 · 1 / 98920 = 0.0% Sep 3 · 2 / 94044 = 0.0% Sep 4 · 1 / 89879 = 0.0% Sep 5 · 0 / 93829 = 0.0% Sep 6 · 0 / 82493 = 0.0% Sep 7 · 0 / 79429 = 0.0% Sep 8 · 0 / 72651 = 0.0% Sep 9 · 1 / 68910 = 0.0% Sep 10 · 0 / 72993 = 0.0% Sep 11 · 1 / 78289 = 0.0% Sep 12 · 0 / 51624 = 0.0% Sep 13 · 1 / 53877 = 0.0% Sep 14 · 1 / 54034 = 0.0% Sep 15 · 1 / 53572 = 0.0% Sep 16 · 0 / 54258 = 0.0% Sep 17 · 0 / 52075 = 0.0% Sep 18 · 0 / 48484 = 0.0% Sep 19 · 1 / 41291 = 0.0% Sep 20 · 0 / 40881 = 0.0% Sep 21 · 0 / 46649 = 0.0% Sep 22 · 1 / 50554 = 0.0% Sep 23 · 0 / 52726 = 0.0%
May 18, 2026 90 days Sep 23, 2026

The shaded part of the chart is measured against a different set of sites. Until 8 July 2026 we only tracked launches from launch platforms; from that date we crawl the wider web as well. The share is a proportion of whatever we were tracking at the time, so it can step at that line without the technology itself changing. For a single continuous measure, switch to launch platforms.

How StackScope detects technologies

⋮ Jul 1, 2026: Adoption figures now count launches from launch platforms. Use the source view to include StackScope Discovery.

Javascript Library leaders

Tool % of launches % of category
#1 – jQuery 14.61% 35.54%
#2 – React Router 6.34% 15.42%
#3 – Motion 5.95% 14.47%
#4 – TanStack Router 4.12% 10.03%
#5 – Swiper 3.74% 9.10%
…
#439 ▼128 Proj4js Current page <0.01% <0.01%

Percentages show adoption among indie launches: the share of all analysed launches, and of launches using any Javascript Library tool.Among August launches it ranked #463 in Javascript Library, down from #335 in July. All 1320 in Javascript Library →

Often used with

Tool Sites
Leaflet 27
cdnjs 24
unpkg 23
jsDelivr 22
Cloudflare 21

Tools most often detected on the same sites as Proj4js.

Recent launches we can show

17 of the 39 sites using Proj4js are product launches we list individually. The other 22 are sites we found crawling the wider web: they count towards the figures above, but we do not publish them one by one. How StackScope Discovery works

Aqalxy | Plans Topographiques et Calculs Géodésiques au Maroc Sep 22, 2026 Rumbo GIS | Convertir KML y KMZ a UTM Online Gratis Sep 14, 2026 FacetWorks Sep 13, 2026 Design NavPlanner — מרכז ניווט Sep 3, 2026 Productivity RUANG KITA | Peta Interaktif & Data Geospasial Indonesia Sep 2, 2026 soilKey Pro Aug 30, 2026 GeoFieldTools - SW Maps to SiteAware GCP Converter Aug 23, 2026 Developer Tools PYRALERTE — Console tactique feux de forêt Aug 21, 2026 Games 지오시프트 · GeoShift — 이미지·PDF·압축·GIS 좌표변환 무료 변환기 Aug 11, 2026 Productivity LidArch — Free LiDAR Map of England & Wales for Archaeology Aug 7, 2026 GeoConvert Pro Aug 4, 2026 Practical Geospatial Solutions — 브라우저 기반 GIS 분석 도구 Jul 28, 2026

Showing the most recent 12 of 17.

The StackScope API serves all 39 sites using Proj4js, filterable and exportable, from £15 a month.

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