In the May 2017 survey we received responses from 1,814,996,345 sites and 6,404,290 web-facing computers. Although the total number of sites has fallen slightly, by 1.4 million since April, the number of computers has grown by 83,000.

Large shifts in site counts

Although it fared well in other metrics (see below), nginx suffered a massive 30% loss of hostnames this month. With a net loss of more than 100 million sites, its market share has fallen by 5.71 percentage points to 13.5%. The majority of the sites that disappeared were Chinese-language spam sites hosted at Amazon Web Services in the United States and Japan.

Meanwhile, Microsoft gained 79 million sites, which has taken its market share up to 49.1%. This is Microsoft's highest market share in the 22-year history of the Web Server Survey, and also reflects a significant change in fortunes over the past year: Last June, Apache had the largest market share of websites, but now Microsoft's share is more than twice as large as Apache's, which fell by a further 1.73 percentage points this month to 20.95%.

nginx leads active site growth

Despite the large loss of hostnames, nginx gained nearly a million active sites, which has taken its active sites share back above 20%. This suggests most of the 104 million hostnames it lost did not have distinct content, and therefore were of little interest to ordinary web users, despite the apparent size of the change.

Apache continues to lead the active sites market quite comfortably with a 45.6% share, although a loss of 1.4 million active sites has brought this down by 0.67 percentage points. nginx stays firmly in second place, with more than twice as many active sites as Microsoft.

nginx's computer growth continues unabated

nginx's consistent computer growth has continued, making it look ever more likely to overtake Microsoft later in 2017. Its gain of 48,500 computers – combined with Microsoft's loss of 6,000 – has reduced the difference in their market shares by nearly a whole percentage point.

nginx is now within 3.46 percentage points of Microsoft's share of 23.8%; but Apache also maintains a comfortable lead in this market – it increased its web-facing computer count by 28,800 this month, keeping Apache's share above 43%.

nginx pushing others out of the top million

nginx is also continuing to make strong progress amongst the top million websites, where it has been ahead of Microsoft for the past few years. It was the only major vendor to increase its presence this month, resulting in thousands of competing vendors' websites being pushed out of the top million. Apache suffered most, with 3,200 Apache-powered sites departing the top million, but it still leads this market with a 40.5% presence.

Apache has exhibited a slow and steady decline over the past several years. Coupled with nginx's consistent growth within the top million sites, the gap between the two is ever decreasing; however, it looks like it will be a good year or two until nginx seriously starts to threaten Apache's lead.

New nginx 1.13 mainline branch

nginx 1.13.0 was released on 25th April. This is the first release on the new, actively-developed 1.13.x mainline branch, adding bugfixes and new features to what was essentially the most recent stable version of nginx (1.12.0).

The most notable new feature in nginx 1.13.0 is its support for TLS 1.3, which aims to be the latest and most secure version of the Transport Layer Security protocol – although not many underlying crypto libraries actually offer TLS 1.3 yet. The TLS 1.3 specification has not yet been finalised, although the working draft has been sufficient for some servers and clients to implement it. For example, Mozilla's NSS cryptographic library – which is used by Firefox – enables TLS 1.3 support by default.

Microsoft IIS Administration API enters general availability

The Microsoft IIS Administration API that we mentioned in February is now Generally Available. The newest 1.1.0 release also facilitates management of the IIS Central Certificate Store, and includes an improved certificate API. These features are intended to make it easier to manage certificates across entire farms of web servers.

LiteSpeed enters the Amazon cloud

LiteSpeed Technologies is now a Technology Partner in the Amazon Web Services Partner Network (APN), coinciding with the release of the LiteSpeed Web Server AMI. This Amazon Machine Image is based on CentOS 7 with the LiteSpeed Web Server pre-installed. AWS users can now use this AMI to quickly deploy ready-to-use virtual machines that run the LiteSpeed Web Server in the cloud.

This month's Web Server Survey found 6.4 million websites running LiteSpeed, which encompasses 2.3 million active sites, more than 2 million unique domain names, and nearly 11,000 web-facing computers. One of the busiest sites currently using LiteSpeed is FanFiction.Net, which is an automated fan fiction archive.

Enter the Beaver

China saw a large number of new sites being served by the relatively unknown "Beaver" web server. Just over a million sites now exhibit the Beaver Server header, and these make use of more than 110,000 unique domain names – mostly under the .cn top-level domain. Most of the sites are hosted by Aliyun, which is China's largest cloud hosting provider, while the majority of the rest are hosted by other Chinese companies. Only a single Beaver site is hosted outside of China – this solitary instance is hosted in Japan, at Amazon's Tokyo AWS region.

The behaviour of these sites suggests that Beaver might not be an entirely new web server, but possibly an application based on Microsoft's HTTP Server API (HTTPAPI 2.0). This API lets C/C++ programmers receive HTTP requests and send responses without using Microsoft IIS. At least 38 million other websites also use HTTPAPI 2.0.

But most of the Beaver sites are currently inaccessible and display the following message: "According to the filing requirements of China's Ministry of Industry and Information Technology (MIIT), the website is accessible only if the ICP information is accurate and the ICP license is filed". An ICP Filing ("Bei'an") is required by all content providers in China before they can use hosting and CDN products, but this only allows them to be used for informational purposes. A Commercial ICP Licence ("Zheng") is required for any website that sells goods or services that directly generate revenue online.

Pepyaka making the web more friendly

The little-known Pepyaka web server has also been quietly growing. This server is used predominantly by Wix, an Israeli company that provides a friendly website building platform to millions of users. Wix provides free website hosting under the *.wix.com domain, or customers can get a free custom domain name when upgrading to one of Wix's yearly premium plans.

This business model has led to a high ratio of domains to hostnames amongst the Pepyaka install base. Wix-hosted websites alone account for 1.4% of all unique domain names in use on the web, which is no mean feat. All of these sites are hosted within the Amazon Web Services cloud, using Pepyaka version 1.11.3. This version number, coupled with Wix's previous uses of nginx, suggests that it could be based on last year's mainline version of nginx.

In the January 2017 survey we received responses from 1,800,047,111 sites and 6,328,006 computers, reflecting a gain of 61 million sites and 159,000 computers.

Microsoft gained the largest number of sites this month – 38 million – although it was closely followed by Apache, which gained 32 million. Nearly 822 million sites (45.7%) are now powered by Microsoft webserver software.

Meanwhile, nginx gained 17 million sites, and has also continued to show strong and steady computer growth. This month's gain of 60,000 web-facing nginx computers was the largest seen by any vendor, outweighing Microsoft's and Apache's gains of 40,000 and 20,000. If last year's trends continue in 2017, it seems plausible to expect that nginx could overtake Microsoft to become the second largest vendor (by computers) in the second half of 2017.

Microsoft's latest version of Internet Information Services – IIS 10.0, which uses Windows Server 2016 as its primary platform – was found powering 45,000 websites this month. Future migration to IIS 10.0 may be slower than with previous IIS versions, however, as Microsoft announced Windows Server Premium Assurance in December 2016, which extends the support period from 10 to 16 years for existing Windows Server products. This means Premium Assurance customers will continue to receive security updates (as well as "critical" and "important" bulletins) for Windows Server 2008 until January 2026. In January 2017, more than 600 million sites are served from Windows Server 2008 machines.

Each of the other major server vendors released updates last month. nginx 1.11.7 mainline version was released on 13 December, followed by 1.11.8 on 27 December. Both releases included several bug fixes and a few new features.

The mainline 1.11.x branch of nginx is typically updated every 4-6 weeks and is aimed at users who require the latest features, whereas the 1.10.x stable branch is only updated when critical issues need to be fixed. Only two updates have been released on the stable branch since 1.10.0 was forked from mainline in April 2016. Stable is the most commonly used branch: nearly 24 million sites are using 1.10.x stable, compared with 2.2 million using 1.11.x mainline.

Apache 2.4.25 was released on 20 December 2016, incorporating security, feature and bug fixes (including many from the unreleased 2.4.24 version). The security fixes include a mitigation for issues caused by the httpoxy vulnerability, and better enforcement of the HTTP request grammar in RFC 7230 to reduce the likelihood of response splitting and cache pollution attacks.

While many sites still use older versions of Apache, such as the 2.2.x legacy versions, the Apache Project continues to point out that the latest release from the 2.4.x stable branch represents the best available version of Apache HTTP Server. Nonetheless, most sites—just over 100 million— report to be using 2.2.x legacy versions, compared with 69 million sites that use 2.4.x. The most commonly observed Apache Server banners are Apache/2.4.7 (Ubuntu) (36 million sites), followed by Apache/2.2.15 (CentOS) (25 million); however, these servers may not necessarily be as old and vulnerable as their version numbers imply. Netcraft previously discussed this "backporting" behaviour a few years ago.

LiteSpeed suffered the largest loss of sites this month, returning to October 2016 levels after plummeting by 42 million sites to leave a total of 5.5 million. Despite the large loss of sites, the number of web-facing computers using LiteSpeed increased modestly by 323 to 9,740. LiteSpeed 5.1.11 was released on 15 December, featuring improved caching and a few bug fixes.

December also saw the release of Tengine 2.2.0 development version, which came nearly two years after the previous development version, and a year after the most recent stable version. Not only does Tengine have a relatively sedate release cycle, but its latest version is based on nginx 1.8.1 (the final version of nginx's previous stable branch), which itself is already a year old.

Despite having relatively infrequent releases, 58 million sites are currently using Tengine. Most of these sites do not reveal which version has been installed, but among the 18 million that do, about two-thirds are using the relatively old 1.4.2 development version which was released in November 2012 and based on the nginx 1.2.x stable branch. Tengine was originally created by the Chinese marketplace Taobao, which modified the nginx core to better suit its requirements. It was released as an open source project in December 2011, and today sites under the taobao.com domain account for only 5% of its users.

In the December 2016 survey we received responses from 1,739,031,487 sites and 6,169,471 web-facing computers; this reflects a large increase of 302 million sites, but a small loss of 55,900 computers.

All three of the largest server vendors gained sites this month, with growth concentrated at a handful of lesser-known web hosting providers. These changes have triggered large jumps in market share, with nginx (+3.2 percentage points) and Microsoft (+1.6 p.p.) gaining, and Apache losing (-2.2 p.p.).

The growth in number of sites was not reflected in other metrics this month, however, with small drops being seen in both the total number of web-facing computers (-0.9%) and the number of active sites (-0.8%).

Nginx was the only major web server vendor to experience gains across all metrics this month, including active sites, web-facing computers, and the million busiest sites. It now stands only 390,000 computers (6 percentage points) behind second place Microsoft, having surpassed Microsoft in terms of active sites in January 2012, and the top million busiest sites in May 2013.

Previously the 10th most commonly seen web server in terms of active sites, “Webs.com/1.0”, has vanished this month after the website builder began using the Cloudflare CDN service. Cloudflare uses a customised version of nginx (cloudflare-nginx), that powered over 3.6 million active sites in the December survey.

Looking back over 2016, the total number of sites seen in the survey has grown significantly, from 900 million in January to 1.7 billion in December. Much of this growth can be attributed to Microsoft, which has gained more than 520 million hostnames and risen from 28.95% market share to 45.07%. However, the more stable active sites metric shows nginx grew the most this year, having increased by 4.8 million active sites and 2.85 percentage points of market share over the course of 2016.

The year also saw the notable rise of OpenResty: in January, OpenResty was being used by 760,000 sites, 200,000 active sites, and just 3,100 web-facing computers; but in September, tumblr.com switched from using nginx to OpenResty for millions of Tumblr blogs. The number of sites using OpenResty in December is now nearly 15 million, the number of active sites is 5.8 million, and the number of web-facing computers seen running OpenResty has increased to nearly 8,000. The server is now the 9th most popular by number of web-facing computers.

Microsoft’s newest web server software, IIS 10.0, was released this year although it is yet to make a significant impact in the number of sites. Windows Server 2016, the primary operating system for running IIS 10.0 was only fully released in October after months of preview releases; the December 2016 survey finds the operating system being used on 5,800 web-facing computers to host 18,250 sites.

Another notable arrival during 2016 were the hundreds of thousands of Western Digital My Cloud personal storage devices. These Network Attached Storage (NAS) devices run an Apache web server and each has a hostname on the wd2go.com domain. The fact that these devices are placed in end-users' homes, using less-stable home Internet connections, and more commonly powered off than a typical web server has increased the volatility of the Apache web-facing computer data. The December 2016 survey found 680,000 sites for these devices.