In the May 2021 survey we received responses from 1,218,423,991 sites across 259,596,021 unique domains and 11,051,830 web-facing computers. This reflects a gain of 6.28 million sites and 112,000 computers, but a loss of 4.87 million domains.

nginx gained the largest number of hostnames, active sites, and computers this month; but also suffered the largest loss of 4.73 million domains. Its most notable gain was of 78,900 computers (+2.03%), which increased its leading share to 36.0%. It also continues to lead in the hostnames and domains metrics, while Apache is top in active sites.

Apache also maintains its lead amongst the top million websites, with a 25.4% share compared to nginx's 22.9%. Cloudflare's share of the top million sites is now up to 17.0% after increasing its presence by a further 3,090 sites, and Microsoft added 1,840 sites to bring its share up to 6.85%.

OpenResty saw the largest decrease of 8.10 million hostnames (-9.88%), which has taken its market share down to 6.06% (-0.7 pp). Microsoft also suffered a large loss of 6.92 million sites (-10.3%), which took its share down to 4.95% (-0.6 pp).

One of OpenResty's most prominent users is Automattic, which uses it to serve millions of Tumblr microblogging websites that can be found under the tumblr.com domain – for example, icontherecord.tumblr.com.

Automattic is also responsible for the popular WordPress.com blogging service, where it instead uses nginx to serve millions of blogs. These WordPress-powered sites can either use custom domain names, or free blogs can be created directly under the wordpress.com domain – for example, catsbeingcats.wordpress.com.

The underlying WordPress blogging software reached its 18th birthday this month. Automattic continues to contribute to this open source project, and the software is freely available from wordpress.org, allowing anyone to download and install the software on other compatible web server platforms. Although Apache and nginx are recommended, any server that supports PHP and MySQL ought to be capable of running a WordPress site. Such is the popularity of WordPress, some hosting providers also provide one-click installers and other tools that make it easy to manage WordPress sites.

Other vendor and hosting news

• nginx 1.20.1 stable and nginx 1.21.0 mainline were released on 25 May. Both versions include a fix for a 1-byte memory overwrite vulnerability.
• NGINX Unit 1.24.0 was released on 27 May. This adds several new features, including SSL/TLS configuration commands, static file chrooting with symlink and mount resolution controls, static file filtering by MIME type, and compatibility with Ruby 3.0. It also includes some bugfixes.
• Caddy 2.4.0 was released on 10 May, with over 110 patches to resolve bugs and add features likes remote API access, automated identity management and dynamic config loading.
• Apache Tomcat 10.0.6, 9.0.46 and 8.5.66 were released on 12 May. Version 1.0.0 of the Apache Tomcat Migration Tool for Jakarta EE was released a few days earlier on 7 May – this is the tool that allows Tomcat web applications written in Java EE 8 to be automatically converted to run on Tomcat 10 which implements Jakarta EE 9.
• To showcase its new architectural paradigm of Workers, WebSockets and Durable Objects, Cloudflare has released a multiplayer Doom port which can be played at https://silentspacemarine.com. This game demonstrates how application code can be run on Cloudflare edge nodes rather than only on a client or server.

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