Companies Using Varnish

I run the crawler that stores the response headers of every domain we visit, and Varnish is a header most site owners never chose. Our October 2026 crawl counts 455,550 domains, 3rd of 12 in Caching with 16.11%, and 267,048 matched to a company. On 16 October 2026 I re-requested a random 600 from the clean set, resolved each address to its network and read every response header.

What the header means

A domain counts when a response carries Via with "varnish" in it or any X-Varnish header. Varnish is a caching reverse proxy, so the header belongs to whoever runs the proxy. The open-source project now goes by Vinyl Cache, "formerly known as Varnish Cache" on its project site, and the headers haven't changed. 556 of the 600 (92.67%) still sent one on the day.

Sales signal: this row tells you a cache sits in front of the site; who configured it is a separate question.

Two operators write most of it

Fastly carried 239 sampled domains (39.83%). Fastly's documentation says its cache servers run software derived from the open-source Varnish daemon. Inside that group, GitHub Pages accounts for 102 domains, Pantheon's WordPress and Drupal hosting 38 and Adobe Portfolio 34, and 65 are other Fastly customers such as gov.uk, the BBC and Nordstrom. One.com carried 188 (31.33%), nearly all answering Via: 1.1 webcache1 (Varnish/trunk) or webcache2, the Danish host's own cache layer.

"Seven in ten Varnish domains are Fastly's edge or One.com's shared hosting. The site owner picked a CDN, a GitHub repository or a hosting plan, and Varnish came with it." - David Thomson, CTO at TechnologyChecker.io

Together the two cover 426 of the 600 (71.00%); one domain showed both. Neither operator is a single customer running Varnish on unrelated sites, so nothing is removed, but the list has to be read through them.

Sales signal: split the list by operator before anything else. Fastly customers buy CDN and edge services; One.com customers buy hosting packages.

Smaller hosts and teams that run their own

135 sampled domains (22.50%) send Varnish headers from somewhere else. 18 sit behind Cloudflare with Varnish at the origin, 13 more are on AWS, 12 are MoxiWorks real-estate agent sites, 10 are on Gandi, 9 on Belgian host Combell and 8 on Acquia's Drupal cloud. The enterprise names here run Varnish in their own stack: Renault Group, La Poste Groupe and Tech Mahindra return their own X-Varnish IDs, and Lidl's US careers site does so behind Akamai.

Sales signal: this fifth, minus the 39 on MoxiWorks, Gandi, Combell and Acquia, is where a Varnish buyer lives, an engineering team that configures caching. Vinyl Cache, Varnish Enterprise, managed CDNs and observability tools all have a conversation here.

How much of it is live

Our title census of the clean set finds 12,924 domains (2.86%) whose last crawled page was a placeholder or error: 3,075 "Hosted By One.com" pages for domains with no site, 1,651 GitHub Pages "Site not found" or "Page not found" pages, 1,096 Adobe Portfolio domains that redirect to Portfolio's "missing" page, plus Dutch hosts' default pages and error pages. That's under the level where we remove a fleet, so they stay in the count. The live sample was worse: 38 domains (6.33%) showed a placeholder or error page, 19 an HTTP error and 9 didn't answer. A failed fetch doesn't change a domain's status.

Sales signal: one row in ten may be a dead site behind a live cache. Check a domain before outreach.

Who the site owners are

70.51% of sized companies have 1 to 10 staff, but 4,661 have more than 1,000, and pre-1960 founders make up 6.94%, high for a hosting-led list. The Netherlands, Sweden, Belgium, Norway and Denmark hold 80,726 matched companies against the US's 63,190. Industries are flat: IT services 3.86%, software development 3.82%, construction 3.65%.

Sales signal: two lists in one. Nordic and Benelux small businesses on One.com, and large organisations behind Fastly or Pantheon. Price and pitch them separately.

Overlap and churn

We don't publish switching rows here, and the overlaps read as layers. 8,742 domains run Varnish and WP Rocket today, 1,471 LiteSpeed Cache, 230 NitroPack and 172 W3 Total Cache. A WordPress plugin behind a Varnish edge is normal. Movement in the monthly line, 375,048 in June to 455,550 in October, comes partly from our side: the domains we crawl turn over every month and our detection widens. 35,020 domains dropped the header on a hostname since 16 March 2026, and 3,092 of those still send it elsewhere.

"When a Varnish header disappears, the usual story is a site that left One.com or a domain that stopped pointing at GitHub. Nobody uninstalled a cache." - David Thomson, CTO at TechnologyChecker.io

Sales signal: a dropped Varnish header is a hosting or CDN event. Watch it as a sign of a site moving.

The stack around it

Across 452,508 clean domains, Apache answers behind the cache on 36.55% and Nginx on 18.44%. WordPress runs on 31.98%, Drupal on 6.26%, Adobe Portfolio on 4.68% and Next.js on 3.91%. One.com appears on 25.03% and our Fastly row on 23.85%, a floor next to the 39.83% we traced to Fastly's network on the day.

Sales signal: the Drupal and Next.js slices are the engineering-led accounts; the WordPress slice mostly isn't.

What it costs

Varnish Software's pricing page says Varnish Cache, the open-source project its products build on, is free and always will be, and its paid products start with a free trial. For most of this list the cost is buried in a Fastly bill or a One.com plan.

Key takeaways

1. 455,550 domains, 16.11% of Caching; 92.67% of a 600-domain sample still sent the header.

2. Fastly carries 39.83% of the sample and One.com 31.33%.

3. GitHub Pages alone is 17.00%.

4. Varnish outside Fastly and One.com is about a fifth, and it still includes smaller hosts; the enterprise teams that run their own are in that group.

5. 2.86% of the clean set showed a placeholder title at its last crawl.

How to use this list

Segment by operator: Fastly, One.com, GitHub Pages, Pantheon, then self-run. Only the last group is likely to have chosen Varnish itself, and even it includes smaller hosts such as Gandi and Combell. Compare with LiteSpeed Cache for the hosting-cache side. The full list of 455,550 domains, with 267,048 matched companies, is on TechnologyChecker.io.