Web server vs application server: Either/or, or so much more?

There are plenty of similarities and differences between a web and application server, but the two can also work together to produce better results when building and managing websites.

What’s the web server vs application server debate all about?

Networks need to be able to serve numerous requests, some of which are extensive, within a very short time and in accordance with the latest security standards. This is only possible if the various programs work together optimally. The client-server model has proven to be a successful system in which tasks and services can be distributed for smooth operation. Two possible instances within this architecture are web servers and application servers. They’re often confused, but despite their similarities they also have numerous differences. We’ll discuss them below. First, let’s take a closer look at the two.

What’s a web server?

When you’re browsing the internet, a web server is like your permanent point of contact. Contents of all websites are stored on such a server and then made available for users. As a rule, these servers are hosted by providers who make their services available to website operators. Larger companies may have their own web server for their internet content and optionally their intranet. The main task of a web server is to transfer data to the client. These are static in the process.

In addition, a web server fulfils several other tasks. These include:

• HTTP caching: To better handle large amounts of data, web servers can buffer elaborate content through caching
• Communication: Errors and successes are shared with the respective browser via status codes or error pages.
• Protocol: All requests are deposited and stored in a log file.
• Security: Web servers provide encryption HTTPS.
• Cookie management: Cookies can be managed by web servers.
• Redirects: Web servers can redirect to another document via a rewrite engine.
• Access restriction: The web server lets you query and confirm identities.

What’s an application server?

An application server provides and executes programs. These include services such as authentication, transactions, directories and databases as well as office programs, administration software and calendars. The client then gains access to these programs. Application servers are often used in the IT infrastructure of large companies. Among other things, this avoids software compatibility issues, strengthens security architecture, and improves performance.

In addition to some specific characteristics that may vary by vendor, application servers have explicit and implicit characteristics. The explicit features are:

• Connection to databases and higher-level services
• Asynchronous communication
• Encapsulation of data sources
• Persistence
• Directory services

In addition, there are some implicit features such as:

• Calibration
• Runtime management
• Logging functions
• Monitoring
• Scalability
• Software lifecycle management

What are the differences between a web server and an application server?

Glancing at the special features, it becomes clear that the two server types do have things in common, but they’re also clearly differentiated by area of application and specification. We’ll show you their differences by comparing web servers and application servers.

Difference 1: Intended use

A web server is software or hardware that helps to access websites via the internet or intranet. Visitors make requests that are answered via the web server. An application server, on the other hand, is a software framework that provides clients with specific programs or access to a database.

Difference 2: Content

A major difference is the type of content handled by the two types of servers. The content that web servers provide is static. The server responds to HTTP requests and performs the functions of a website. The content that’s hosted and delivered may be, for example, text, images, JavaScript, or CSS. An application server, on the other hand, delivers dynamic content. It provides the business logic for apps using various protocols. These protocols can be HTTP.

Difference 3: Main features

There are also major differences in terms of main functions. The main feature of the web server is the consistent provision of HTML, PHP and ASP files for the respective web browsers. If a user then accesses the corresponding web page, its contents are immediately delivered. The application server provides various applications that can be used by any client in a network.

Difference 4: More features

Web servers can also be used for some other applications. For example, some games, enterprise applications or data storage rely on a web server for support. In addition to its main function, the application server also provides web-based software and enterprise-based programs.

Difference 5: Use of resources

A big difference emerges in the use of resources. Compared to a web server, an application server usually requires significantly more resources. This is due, in particular, to larger files and longer processes. The data traffic is significantly higher when using an application server than a web server.

Difference 6: Multithreading

Multithreading means the simultaneous processing of several tasks or the parallel execution of different processes. This mode of operation is supported by the application server, which allows multiple requests to be processed at the same time. A web server, on the other hand, does not offer this option, instead always executing tasks one after the other.

Difference 7: Architecture

The architecture of a network with a web server is much simpler. Here, a client sends a request in HTTP format directly to the web server. The server accesses a database and returns the requested files in the form of an HTTP response. The structure is comparatively simple and uses the most direct paths possible.

The application server, on the other hand, is located between the web server and the database. In this case, the client also sends an HTTP request to the web server. This sends it on to the application server, which in turn converts it into a servlet request and sends it to the database. There the request is processed and sent back to the application server. The application server passes the response to the web server, which converts it back into HTTP format and passes it to the client. Dynamic content can also be made available in this way.

Difference 8: Provider

The most popular and widely used web server providers include:

• Apache HTTP Server
• Caddy
• Cherokee
• LiteSpeed Web Server
• Microsoft IIS
• NGINX

The most popular application servers are:

• Apache Tomcat
• IBM CICS
• LiteSpeed Web Server
• NGINX
• Oracle Web Logic
• Red Hat JBoss Enterprise Application Platform
• Wildfly

There are commercial and open-source solutions for both web and application servers.

Can the two servers work together?

Although there are some major differences in the architecture of web servers and application servers, they can be used together. If a website plans to offer static and dynamic content, it’s worth combining the two server types. The web server forwards the requests to the application server and returns its responses to the client. So, an either-or decision is not always necessary. Some application servers already contain web servers.

Web server vs. application server: Which one is the right choice?

Since the web server is primarily responsible for the continuous and rapid display of website content, and the application server is primarily responsible for the business logic and availability of various applications, you may be asking yourself which server type is most suitable for your website.

If you only want to include static content on your website, go with a web server. If you have dynamic content, use a combination of a web server and an application server.

However. the number of websites only displaying static content is dwindling and such websites may become obsolete in the future. The boundaries between a web server and application server are also becoming increasingly blurry. It makes sense then to regard web servers and application servers as two options for tailoring your website instead of as opponents. To meet the demands of modern websites, popular providers such as Apache or NGINX already offer a combination of both server types.