6 Open Source Web Servers for Small to Large Sites

A web server is a critical component of any website or web application. It is responsible for accepting HTTP requests from clients and serving pages and assets to display in the browser. There are many open source web server software options to choose from, each with their own strengths and weaknesses. In this comprehensive guide, we will explore the top 6 open source web servers and help you determine which is the best fit for your specific needs.

Overview of Web Servers

Before diving into the specific web server options, let‘s first understand what a web server does and key features to look for.

The core responsibilities of a web server include:

• Accepting HTTP or HTTPS requests from clients and returning appropriate responses
• Serving static assets like HTML pages, images, CSS files, JavaScript
• Interfacing with application code to generate dynamic responses
• Managing network connections and HTTP protocol
• Handling caching, compression, security, access control

Some key features and criteria to evaluate web servers on:

• Performance – can it handle high traffic loads, throughput, and concurrency? Handles caching and compression well.
• Scalability – easy to scale horizontally across multiple servers.
• Security – SSL/TLS support, access controls, vulnerability history.
• Customization – flexibility to customize and extend functionality.
• Ease of use – installation, configuration, and maintenance overhead.
• Support – quality of documentation, community, and commercial support options.
• Resources – efficient memory, CPU, and storage resource usage.

With these criteria in mind, let‘s look at the most popular open source web server options available today.

1. Apache HTTP Server

The Apache HTTP Server, colloquially called Apache, is the most widely used web server software. Developed and maintained by the Apache Software Foundation, it is open source software and available for free.

Apache played a key role in the initial growth of the World Wide Web. Originally released in 1995, it has been the most popular HTTP server for much of the history of the Web. Apache quickly overtook early web server software like NCSA HTTPd and CERN httpd.

Why Apache is Popular

Here are some of the key advantages and reasons for Apache‘s dominance as the #1 web server:

• Cross-Platform – Apache runs on a wide variety of operating systems including Linux, Windows, MacOS, and more.
• Open Source – Apache is open source with permissive licensing, allowing free use and modification.
• Extensible – Functionality can be extended with modules andmods_rewrite allows URL rewriting.
• Battle-tested – Apache‘s longevity proves it is stable, secure, and reliable.
• Customizable – Many customizable configuration options for security, performance tuning, etc.
• Wide Support – Abundant documentation, tutorials, commercial support available.
• PHP Integration – Tight integration and optimization for running PHP via mod_php.

Apache excels at serving both static and dynamic content. It runs well on cheap commodity hardware and can handle hundreds of thousands of simultaneous connections with the proper tuning and mods. The event-driven architecture introduced in Apache 2.4 further improved scalability and performance.

For WordPress and PHP-based sites in particular, Apache‘s close integration makes it a smart default choice. The .htaccess configuration files also make it easy to customize on a per-directory basis.

When to Consider Alternatives

While Apache HTTP Server is a great all-around choice, other web servers may be better suited for certain use cases including:

• Maximum Performance – Alternative servers like Nginx handle concurrency better out of the box.
• Static Content – Nginx and Caddy have more optimizations for serving only static files.
• Low Resource Usage – Options like Lighthttpd have lower memory and CPU requirements.
• Highly Customized – Nginx is extremely customizable with advanced modules available.

2. Nginx

Nginx (pronounced "engine-x") is a lightweight and high-performance web server created by Igor Sysoev in 2002. It emerged as an alternative to Apache optimized for maximum concurrency, high traffic loads, and low resource usage.

Nginx follows an asynchronous, event-driven model more akin to Node.js. This allows it to handle thousands of concurrent connections with low memory usage. Combined with efficiency features like caching, compression, and static file handling, it often outperforms Apache.

Why Consider Nginx

Here are some of the advantages of using Nginx for your web server:

• Performance – Excellent for serving high-traffic sites and applications due to its asynchronous architecture.
• Scalability – Easy to scale horizontally by adding more Nginx servers behind a load balancer.
• Concurrency – Can support over 10K concurrent connections on a modern server.
• Static files – Optimized for speedy static file serving, compression, and caching.
• Reverse Proxy – Often used as a lightweight reverse proxy and load balancer.
• Small Footprint – Low memory usage and CPU demands compared to Apache.
• Advanced Modules – Additional modules provide advanced features and customization.

Companies like Airbnb, Netflix, Pinterest, and Cloudflare rely on Nginx to serve their high-demand sites and apps. It‘s become especially popular for fronting applications built with Node.js, Ruby on Rails, and PHP via FastCGI.

If you need raw speed and efficiency to handle huge traffic volumes, Nginx will likely outperform Apache and many other web servers.

Downsides of Nginx

The advantages of Nginx come with some tradeoffs to consider as well:

• Complex Configuration – Config files are not as intuitive as Apache and can be tricky.
• Steeper Learning Curve – Due to the asynchronous architecture and customization options.
• Limited Dynamic Support – Must proxy to other apps like Node or PHP-FPM for dynamic content.
• No .htaccess – Nginx does not support per-directory .htaccess configuration files.

For many simple usage cases like standard LAMP/LEMP stacks, Apache may actually be easier to work with than Nginx. But for a high-traffic site, Nginx can better handle the load.

3. Caddy

Caddy is a relatively new open source web server that offers an intriguing alternative to Apache and Nginx. Created by Matthew Holt in 2015, Caddy‘s key advantages are being easy to use and offering "batteries included" features like default HTTPS support.

Caddy aims to make web servers easy and approachable without sacrificing capability. Here are some of its standout features:

• Automatic HTTPS – Enables HTTPS by default for all sites using Let‘s Encrypt SSL certificates.
• Simple Configuration – Quick to set up with a human-friendly config syntax. No separate virtual host configuration.
• HTTP/2 Support – Enables HTTP/2 by default for faster page loads.
• Minimal Resource Usage – Efficient Go-based executable with low memory footprint.
• Plugin Architecture – Additional functionality available via plugins like basic auth, cache control, and more.
• Extensible with Caddyfile API – Customizable by writing apps that hook into Caddy‘s Caddyfile API.

For basics like serving a static site or configuring WordPress to use HTTPS, Caddy makes it shockingly simple. You get modern protocol defaults like HTTP/2 without any extra hassle or configuration.

Advanced users may find the configuration limits constraining at times, so Caddy won‘t replace Nginx for complex setups. But for smaller scale sites and team members less familiar with web servers, Caddy is a refreshingly lightweight option.

4. OpenLiteSpeed

OpenLiteSpeed is an open source web server developed by LiteSpeed Technologies, Inc that originated from the commercial LiteSpeed server. It aims to offer excellent compatibility with Apache along with improved performance.

Here are some key features of OpenLiteSpeed:

• Easy Migration from Apache – Very compatible with Apache‘s mod_rewrite rules and .htaccess configs.
• Performance – Event-driven architecture for high throughput and concurrency. Benchmarks faster than Apache in tests.
• Web-Based Admin – Includes a web UI for administration instead of CLI configuration.
• Optimized for PHP – Used as a replacement for Apache + mod_php with faster PHP handling.
• HTTP/2 Support – Enables HTTP/2 support by default.
• PageSpeed Optimization – Various performance best practices automatically applied to pages.

For those running WordPress or other PHP apps on Apache, switching to OpenLiteSpeed can potentially double or triple performance. The project also receives regular updates and improvements.

The web UI may not offer quite as much control as Nginx‘s configuration files. But OpenLiteSpeed provides a user-friendly alternative to optimize PHP-based sites.

5. lighttpd

lighttpd (pronounced "lighty") is an open source web server optimized for speed, security, and low resource usage. It is designed for high performance environments and to be a lean alternative to Apache and Nginx.

Here are some details on lighttpd:

• Performance – Optimized architecture for memory efficiency along with a small codebase written in C. Benchmarks very fast compared to some competitors.
• Low Resource Usage – Extremely lightweight, with memory usage potentially 5-10x less than Apache in tests. Made for embedded devices.
• Secure – Has a strong security focus, with minimal vulnerabilities discovered over its lifetime.
• Flexible – Many aspects of core functionality are configurable or extendable with plugins.

lighttpd excels in applications where you need to serve traffic very efficiently in terms of memory and CPU usage. For example:

• High-traffic sites on hardware-constrained servers or VPS instances.
• Internet of Things devices.
• Smaller instances like Raspberry Pis.
• Very large deployments distributed across hundreds of servers.

It meets a niche for environments where performance per unit of resource usage is critical. The simplicity can be beneficial, as lighttpd lacks some of the higher-level features of Nginx that add overhead.

When lighttpd Falls Short

There are some disadvantages to lighttpd to consider as well:

• Single-threaded – Cannot take advantage of multiple CPU cores, limiting overall throughput.
• Limited Concurrency – Not well-suited for workloads over a few hundred concurrent requests.
• Few Advanced Features – Lacks built-in load balancing, SSL termination, compression, caching, and other higher level features. These would need to be handled externally.
• Not as Well Supported – Documentation and community aren‘t on par with Apache and Nginx.

For the majority of users, lighttpd lacks the features and scalability options offered by other servers. But it remains a great choice for constrained environments where scraping out maximum performance from limited hardware resources is critical.

6. Cherokee

Cherokee is an open source, cross-platform web server that boasts ease of use, configuration, and administration. It is positioned as a fast, flexible, and lightweight alternative to the likes of Apache.

Key features of Cherokee include:

• Web Admin Interface – Configuration and administration through a web GUI instead of configuration files.
• Fast – Benchmarked faster than some competitors in tests. Uses an event-driven, multi-threaded architecture.
• Lightweight – Small memory footprint in a similar vein to Nginx.
• Flexible – Supports plugins for extending functionality.
• Scalable – Multi-threaded and multi-core friendly design.
• Secure – Includes robust SSL, authentication, and access control features.

For less experienced users, Cherokee offers one of the most gentle learning curves. The web admin interface allows most common operations like managing virtual hosts, SSL certificates, caching, and file handlers without touching configuration files.

Cherokee likely won‘t scale or perform quite as well as Nginx or OpenLiteSpeed. But it can still capably serve small to medium scale sites with easy administration and lightweight resource usage.

Honorable Mentions

There are a few other open source web servers worth quick mention:

• Jetty – Focused on Java web apps. Often embedded as a Java servlet container.
• Vert.x – Polyglot event-driven framework with a web server component.
• RoadRunner – High-performance PHP server alternative to PHP-FPM.
• Apache Traffic Server – High-performance caching proxy server.
• Netty – Async server framework in Java. Can power web servers through Socket.io.
• Resty – Lua-based Nginx scripting framework for customization.
• OpenResty – Bundle of Nginx with Lua modules for extensibility.

Web Server Operating Systems

The web server software provides the core functionality for handling requests and delivering content. But the base operating system (OS) also plays an important role in security, performance, and compatibility.

Most common choices include:

• Linux – Most web servers run best on Linux. Ubuntu, CentOS, Debian, and RHEL are popular server Linux distros.
• FreeBSD – Performs well for servers. Often used with Nginx.
• Windows Server – Common for .NET, ASP, and Windows-centric tech stacks. IIS is the default server on Windows.
• macOS – Can run web servers for local development. But not ideal for production.

Linux is most common for open source web servers, with CentOS or Ubuntu LTS releases being safe choices. This avoids dependence on a particular distro.

For maximum security, using an immutable OS like Photon OS as the base for container deployments is recommended. This reduces the attack surface dramatically by omitting unnecessary packages.

Choosing the Best Web Server

So with all these open source web server options, how do you choose the right one? Here are some key considerations when selecting a web server:

• Language/Framework – If married to a particular language or tech stack, choose the web server that best integrates with it. For example, Apache for PHP or Jetty for Java.
• Traffic Volume – Higher traffic sites need highly concurrent servers like Nginx or OpenLiteSpeed.
• Type of Content – Static content benefits from Nginx, while WordPress favors Apache or OpenLiteSpeed.
• In-house Expertise – Pick a server that aligns with your team‘s experience, unless aiming to learn something new.
• Resources Available – lower resource servers like Lighttpd can serve more sites on constrained hosting.
• Ease of Use – Beginners may prefer Cherokee or Caddy for easiest administration.

There is no single best web server for all scenarios. Evaluate your specific needs and environment to determine the optimal fit.

For most common situations – like running WordPress or a basic LAMP stack – Apache HTTP Server provides a robust all-around solution. But other options like Nginx, Caddy, and OpenLiteSpeed warrant consideration for the right use cases.

Benchmarks

Web server performance can vary significantly depending on workload, hardware, OS, configuration, and many other factors. But benchmarks can provide a general comparison, with the caveat that your mileage may vary in real-world usage.

Some sample benchmark numbers with a static and dynamic test:

Web Server	Requests/sec (Static)	Requests/sec (Dynamic)
Nginx	95,047	61,593
OpenLiteSpeed	69,852	78,255
Apache	63,225	22,924
Caddy	43,200	18,182
Cherokee	33,233	7,256

Nginx excels for static content with OpenLiteSpeed close behind followed by Apache. For PHP workloads, OpenLiteSpeed edges out Nginx. But remember these are micro-benchmarks on a particular workload – your specific environment and traffic patterns will impact this significantly.

Conclusion

Open source web servers provide the foundation for hosting fast and efficient sites and applications. While historically dominated by Apache, alternatives like Nginx, OpenLiteSpeed, and Caddy have risen to prominence as well.

Consider your performance requirements, traffic levels, type of content, team skills, and ease of use when selecting the optimal web server. For most common use cases, Apache HTTP Server delivers a reliable all-around option. But other choices like Nginx or OpenLiteSpeed warrant evaluation to see if they may be a better fit depending on your stack and needs.

By understanding the strengths of each leading web server, you can choose the right foundation for serving your web content and applications to the world.