jsDelivr: fourth by reach, and utterly average on every other measure

Enormous reach, median behaviour

jsDelivr's distinction in this index is reach and only reach. On every other measure the pages carrying it sit close to the middle of the 88 companies: 8 companies contacted at the median (rank 47 of 88), 2 classified trackers (rank 40), 45 requests (rank 43), 93.4% of sites with early contact (rank 46), 6 companies contacted before the window closed (rank 37, level with 19 others) and a median first contact at 649 ms (rank 52). In each case rank 1 is the highest value.

That is an unusual profile. Most companies with this much reach are attached to a specific kind of page — an ad stack, a newsroom, a shop. jsDelivr is attached to the ordinary web. A page that pulls one library from a public CDN could be anything, and in this corpus it is.

480 of 514 sites made contact before a banner could be answered

480 of the 514 sites had reached a third party before the opening window closed — the point at which a visitor could first have answered a banner. The quickest single site in the group made its first outbound contact at 55 ms.

This is a fact about the sites, not about jsDelivr. Which company got there first is not something the crawl retains: early contact is stored as a number per site, not as names, so no arrival on those 480 pages can be pinned on anyone. What it supports is the co-presence: jsDelivr was on 480 sites where something was reached early. A script tag pointing at a CDN does load in the head, which is where early contact comes from, but this measurement cannot single it out.

Half these sites carry a banner, and the mix is split

Consent software was detected on 264 of the 514 sites, just over half. An IAB TCF framework banner was seen alongside on 121 of them, OneTrust on 97, Cookiebot on 18, CookieYes on 12, Osano on 11 and Usercentrics on 3. A site can run more than one banner, so these are sightings rather than a breakdown of the 264.

The near-even split between TCF and OneTrust is itself the point. TCF concentrates on pages that sell advertising inventory; OneTrust turns up on corporate and enterprise sites. Finding both in roughly equal measure is what a genuinely general-purpose dependency looks like from the network side.

Google on four fifths of them, and rival CDNs alongside

Google was present on 412 of the 514 sites (80.2%), then Cloudflare on 120 (23.3%), OneTrust on 87 (16.9%), Amazon CloudFront on 76 (14.8%), Cloudflare Analytics on 51 (9.9%), the Meta Pixel on 45 (8.8%), unpkg on 41 (8%), the jQuery CDN on 41 (8%), amazonaws.com on 39 (7.6%) and Adobe Fonts on 35 (6.8%).

unpkg and the jQuery CDN are jsDelivr's direct equivalents — the same job, different operator. Each appears on 41 of these 514 sites, around one in twelve, and every one of those pages is therefore reaching at least two public code CDNs in a single load. That usually is not a decision; it is the residue of a theme, a plugin and a hand-written snippet each picking their own source.

The named sites span everything

zoom.us contacted 5 companies, all 5 inside the window, first contact at 440 ms behind OneTrust. checkpoint.com: 6 companies, all 6 inside, at 222 ms. launchdarkly.com: 9 with all 9 inside, at 249 ms behind Cookiebot. criteo.com is the heaviest here at 12 companies with 8 inside the window, at 495 ms. adobe.io reached 8 with 6 inside at 1,024 ms, unity3d.com 7 with 6 at 992 ms, bit.ly 7 with 5 at 920 ms.

The academic end is lighter: doi.org with 3 companies all inside the window at 265 ms, researchgate.net with 5 all inside at 415 ms, springer.com with 4 all inside at 1,055 ms. smartadserver.com reached 7 with all 7 inside at 667 ms and no banner detected. digicert.com is the only one of the twelve where nothing arrived early — 5 companies, none inside the window, first contact at 2,408 ms.

A certificate authority, a video conferencing service, an ad exchange, a publisher of academic journals and a URL shortener are not one market. They are five, and the same free CDN sits under all of them. If you want to see which CDNs a page of your own reaches, MurmStack lists them in the browser.

Seen on the same pages

Companies most often contacted by the same sites. Co-presence only — the crawl records what arrived, not who called whom.

• GoogleTogether on 412 of these sites
• CloudflareTogether on 120 of these sites
• OneTrustTogether on 87 of these sites
• Amazon CloudFrontTogether on 76 of these sites
• Cloudflare AnalyticsTogether on 51 of these sites
• Meta PixelTogether on 45 of these sites
• unpkgTogether on 41 of these sites
• jQuery CDNTogether on 41 of these sites