What Is Open Source Software? And Why It Runs the World

What open source actually means

Open source software is software whose source code, the human-readable instructions that make it work, is publicly available for anyone to view, use, modify, and share. Contrast that with 'closed source' or proprietary software (like Windows or Photoshop), where the code is a secret owned by a company. With open source, the recipe is public: you can see exactly how it works, fix it, improve it, or build something new on top of it. That openness is the whole idea.

Open source is not just 'free'

A common confusion: open source is usually free of cost, but the deeper meaning is freedom, not price. The classic phrase is 'free as in freedom, not free as in beer.' Freeware (like some closed apps you download at no charge) is free of cost but keeps its code secret. Open source is about the rights to inspect and change the code, whether or not money changes hands. In fact, companies build profitable businesses around open source through support, hosting, and services.

How licenses make it work

Open source is defined by its license, the legal terms that grant those freedoms. There are two broad camps. Permissive licenses (like MIT and Apache) let you do almost anything, including using the code in closed, commercial products, with minimal obligations. Copyleft licenses (like the GPL) require that if you distribute a modified version, you must also share your changes under the same open license, keeping derivatives open. Choosing a license is how a project decides how freely its code can be reused.

Why it is often more trustworthy

Because anyone can inspect open source code, bugs and security flaws can be found and fixed by a global community rather than hidden inside one company. This transparency is a genuine security advantage, especially for sensitive software like encryption tools, where 'trust us, it is secure' is weaker than 'here is the code, verify it yourself.' It is not automatically more secure (unmaintained projects can languish), but the ability to audit and the many eyes on popular projects are real strengths.

It quietly runs everything

Open source is not a niche, it is the foundation of modern technology. Linux runs most of the world's servers and supercomputers and is the base of Android. The web runs on open source (browsers' engines, web servers, programming languages, and countless libraries). Even Apple and Microsoft build on and contribute to open source heavily. Tools like Firefox, VLC, LibreOffice, Blender, and Signal are open source apps millions use daily. Odds are you rely on open source constantly without realizing it.

Why companies embrace it

It might seem odd for businesses to give code away, but the logic is strong: shared development means everyone benefits from collective improvements instead of each company rebuilding the same tools; open standards prevent lock-in; and open sourcing can build ecosystems, talent pipelines, and trust. That is why giants release major projects openly (Google's Kubernetes and Android, Meta's React and PyTorch, Microsoft's VS Code). For users and developers, open source means more control, no lock-in, and the freedom to learn from and build on the best software in the world.

Related on Skillo

See also: How to choose a Linux distro, Git basics: a beginner's guide.

Sources

• Open-source software - Wikipedia

Published date reflects the original event date (2026-03-11). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.