Open source

There is much more to the term “open source” than just software that is accessible by the public and can be viewed, copied, or exchanged by and between third parties. Over the last decades, open source has developed into a mode of working and a movement for collective problem-solving. Due to the decentralized production model, however, open source software is reliant on peer review (an independent process for quality assurance) and input from programming communities. This collaboration is one of the main characteristics of “open software”. This article provides a precise definition of open source and a clear distinction between free, open, and closed software.

What is open source?

Open source originates from the term “open source software”, or OSS for short. With this type of software, the source code is freely accessible. Programmers and users can change and share it. Compared to proprietary software, open source products are more flexible and cheaper to purchase. Open source software does not belong to any individual or company. A large developer community maintains the code and continuously improves it through collective input. Sometimes, organizations and companies join forces on open source projects to save development costs.

This software development process is far from new: In fact, open source is as old as the Internet itself. In the 1950s and 1960s, the first telecommunications network protocols were developed in an open environment. The ARPANET (Advanced Research Projects Agency Network), which laid the foundation for the modern Internet, was based on collaboration and peer review, much like today’s open source software. Hacker movements of the 1970s and the free software movement of the 1980s strengthened the idea of a free knowledge exchange in software development. Today, open source describes not only an “open software”, but also a collaborative attitude in the IT world.


Open source: Open source is the central principle of open source software: software whose source code is publicly accessible and can be changed or copied at will. The decentralized open source concept is based on a strong collective idea: the input of a large developer community that solves problems by freely exchanging knowledge, maintaining, and improving the product for all users.

What is the difference between free, open, and closed source software?

Before open source caught on, publicly accessible software models were referred to as “free software”. This can be traced back to the GNU project. GNU is an operating system that emerged during the free software movement to allow end users maximum freedom in using source code. “Free software” stood in direct contrast to proprietary or “closed software” where only the registered owner (company) is legally permitted to access the source code and can change or share it. Users can only use the software for its intended purpose and upon payment.

However, the term “free software” caused confusion. The word “free” means not only open, but also free of charge. However, free was meant to describe that software could be accessed by anyone and not that it was free of charge. As with Creative Commons, not “everything is allowed” when it comes to open source software: There are certain conditions linked to its use. To steer the focus away from the commercial idea toward free use, the Foresight Institute coined the term “open source” in 1998.


Open source software differentiates from public domain software, also referred to as freeware or public domain software. However, since the terms are not clearly delimited from one another, the two software terms can overlap.

What to consider with open source?

During the early stages, companies were skeptical of the use of open source software. On the one hand, they feared becoming vulnerable under license laws and, on the other hand, they worried about disclosing parts of their proprietary software. The majority of these fears have now disappeared, and many large companies rely on open source solutions. To be able to integrate the broadest possible developer base worldwide, different licensing models have been developed. The majority of the provisions relate to user obligations in regard to the documentation and disclosure of the use of open source projects.

Before you make use of open source components, it is advisable to check the licenses under which they are made available. To avoid legal problems, it is important to use individual components exclusively in accordance with the license conditions and to ensure that their use is documented. If asked, you must be able to openly present your tools and source codes. Developer platforms such as GitHub, which is commonly used to manage software development projects, and licensing tools make the legally compliant handling of open source software much easier. A so-called “software parts list” can be created to keep track of the licenses of the software components you use.

Examples of open source software

The majority of Internet users regularly use software that is distributed under an open source licensing model without realizing it. Below are three successful open source projects that are world-famous and have significantly influenced the OS movement.

PHP: The scripting language was developed to create dynamic web pages. Since its first publication in 1995, it has been one of the most widely used web programming languages worldwide. PHP offers applications such as Slack or Spotify a high level of flexibility when it comes to database support and Internet protocol integration.

Mozilla Firefox: Mozilla Firefox is a freely configurable browser that offers a huge selection of plug-ins and is one of the three most used web clients worldwide. It was launched in 2002, and its open concept caused big waves among the tech industry. According to US news site CNET, Mozilla Firefox played a central role in the spread of open source.

WordPress: The free content management system WordPress has been around since 2003. Ever since, the project has been continuously expanded. WordPress is based on the open source programming language PHP and was originally developed to create and manage blogs. With the integration of external plug-ins, the CMS now offers users effortless configuration options. Today WordPress is one of the most popular and most used content management systems worldwide.

Advantages and disadvantages of open source software

There are numerous arguments in favor of using open source software. However, there are some risks associated with their use, which you should be aware of before using them. Consider the following advantages and disadvantages of open source to see if the software model is suitable for you.


  • Low costs: Source code of open source software is provided free of charge in most cases, drastically reducing its acquisition costs.
  • Reliability: Because an entire developer community is working to improve the product means it is more reliable than proprietary software.
  • Longevity: Open source software is persistent because it is not tied to the success of a single provider whose services would be lost if their business was dissolved.
  • Security: The developer community recognizes and fixes bugs and security threats as soon as they appear.
  • Flexibility: Open source gives users a high degree of flexibility so that the software can be adapted to their own needs without the consent of a provider.


  • Long-term costs: With open source projects, certain follow-up costs may arise, for example, having to train employees or troubleshoot externally.
  • Support: While customer services such as troubleshooting are included with proprietary software, OSS users have no direct contact.
  • Ease of use: Open source software is aimed at developers and requires a certain technical understanding for configuration.
  • Shutdown: Although most open source projects are long-lived, there are times when a project loses the attention of the developer community.
  • Security: Generally, the use of open source projects is safe. Nevertheless, it should be noted that the software is often created in an uncontrolled environment in which malware could be more easily integrated.

Considering its many advantages, it is not surprising that the open source concept has prevailed over the past few decades. Equipped with the right tools, open source users benefit from the software and become part of a global IT movement that relies on collective value creation.

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