Virtually the entire modern internet runs on open-source software. Server operating systems (Linux), web servers (Apache, Nginx), programming languages (Python, JavaScript, PHP), databases (MySQL, PostgreSQL), the Chromium browser engine (the foundation of Chrome, Edge, and dozens of other browsers) – all are open-source projects. Many of them are developed by volunteers and are freely available to everyone.

How and why does this work? Let’s break it down.

What Does “Open Source” Mean?

Source code consists of instructions written by a programmer that a computer (after compilation or interpretation) transforms into a working program. It’s the “recipe” for an application.

Most commercial programs are delivered only in compiled form – you get a working program, but you cannot read exactly how it’s built, modify it, or distribute a modified version. This is the proprietary model (closed source).

Open Source means that the program’s source code is available to everyone for study, modification, and distribution under the terms described in its license.

Important clarification: open source does not necessarily mean completely free in every context – the terms are defined by the specific license. However, in the vast majority of cases, open-source projects are indeed free to use.

Different Licenses – Different Rules

There are dozens of open-source licenses that regulate what can be done with the code in different ways.

GPL (GNU General Public License) – a “viral” license: if you use GPL code in your product and distribute it, your product must also be GPL. This ensures that derivative works remain open. Linux uses GPL.

MIT License – very permissive: do whatever you want with the code, including in commercial products, but retain attribution to the authors. Most popular JavaScript libraries use MIT.

Apache License – similar to MIT, but contains more explicit provisions regarding patents.

BSD License – a family of licenses similar to MIT, used in BSD-family operating systems.

Why Do Huge Corporations Participate in Free Projects?

This is one of the most intriguing questions about Open Source. Google, Microsoft, Meta, Amazon, Red Hat, IBM spend millions of dollars developing code that they then give away for free. Why?

Strategic interests. Influence the development of technologies that the company actively uses. If you depend on a certain tool, it’s better to participate in its development yourself than to be completely dependent on others’ decisions.

Attracting developers. Companies actively involved in popular open-source projects find it easier to attract talented developers who want to work with these technologies and respect the philosophy of openness.

Reducing duplicated efforts. Why should every company develop its own HTTP server or JSON parser when they can jointly maintain a common solution that improves with the collective contribution of all participants?

Reputation and trust. Open-source projects undergo public audits by millions of developers – this makes them more reliable and builds trust in the company within the engineering community.

The Story That Changed Everything: Linux

In 1991, Finnish student Linus Torvalds wrote a small operating system kernel and published the code online, inviting other developers to participate. No one anticipated what would grow from it.

Today, the Linux kernel is over 27 million lines of code, developed by thousands of developers worldwide, including employees from Google, Microsoft, Intel, Red Hat, and hundreds of other companies. Linux runs on 96% of the world’s servers, on all top-500 supercomputers, on most network equipment, on Android (a mobile operating system with a billion-strong audience), and in countless embedded systems.

It is arguably the most significant collaborative engineering project in human history.

How the Open Source Community Works

Most large open-source projects are hosted on GitHub, where developers can view the code, propose changes (pull requests), report bugs, and discuss project development.

Projects usually have core maintainers – developers with the right to accept or reject proposed changes. Communities of contributors form around projects – from professional developers paid by companies to work on open source, to volunteers contributing their free time.

Open Source in Your Life Right Now

Even if you’ve never consciously chosen open-source programs, you use them constantly.

The Chrome browser is based on the open-source Chromium engine. Android runs on the open-source Linux kernel. VLC media player is open source. LibreOffice is an open-source alternative to Microsoft Office. The Firefox browser is completely open source. Most websites you visit run on open-source server software.

Criticism and Limitations of Open Source

Not everything is perfect in the world of open source. Many projects critical to the entire internet are maintained by one or two volunteers without stable funding – this is called the “heart of the internet problem,” and sometimes leads to critical vulnerabilities that go unnoticed for years (as in the case of Heartbleed in the OpenSSL library).

The openness of code does not guarantee its quality or security. Injecting malicious code into popular open-source packages is a real attack vector that has affected a number of major security incidents.

The commercial sustainability of open-source projects remains a constant challenge: how to ensure stable funding for development without losing the principles of openness.

Conclusion

Open source is not just a philosophy or altruism, but a proven effective software development model that underpins most of the modern digital infrastructure. Understanding open-source principles helps you make more informed software choices, grasp technological trends, and evaluate arguments about the security, transparency, and trustworthiness of various software products.