When you use a web browser, a messaging app, or a website builder, you are probably using software made by a company that keeps its code secret. But a huge part of the internet runs on a different idea: open source software, where the code is public and anyone can look at it, learn from it, and help improve it. If you have ever wondered how free tools like Firefox, WordPress, or the Linux operating system can be so good, the answer is open source.
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The Simple Definition
Open source software is software whose source code — the human-readable instructions that make the program work — is made freely available for anyone to view, use, modify, and share. Most commercial software is closed source: you can use the finished program, but you cannot see how it was built, and you are not allowed to change it or pass a modified version to others.
Open source flips that model. The code lives in a public place, usually a repository on a site like GitHub, and it comes with a licence that spells out what you are allowed to do with it. That licence is what makes it “open” in a legal sense, not just in spirit. Different licences have different rules, but the core freedoms are the same: run the program for any purpose, study how it works, change it, and share your version.
It is important to know that open source does not always mean free of charge, although most open source software is free to download. A company can charge for support, training, or a hosted version of an open source tool. What is free is the code itself and the freedom to use it.
A Short History, in Plain Words
The idea began long before the term “open source” existed. In the early days of computing, programmers at universities routinely shared code with each other. As software became a business in the 1980s, companies began keeping code secret, and a programmer named Richard Stallman started the free software movement to defend the freedom to share and modify programs.
In 1991, a Finnish student named Linus Torvalds released the first version of Linux, an operating system kernel, and invited others to help build it. Thousands of volunteers joined in, and Linux grew into one of the most important pieces of software in the world. The term “open source” itself was coined in 1998 as a friendlier, business-oriented name for the same idea. Today, open source powers most of the web: the servers that host websites, the browsers many people use, and the tools that developers rely on every day.
Why Do People Give Their Work Away?
This is the question every beginner asks, and the answers are more practical than they sound. Some developers contribute because they use the tool themselves and want it to be better. If a programmer finds a bug in a tool they depend on, fixing it helps them as much as it helps everyone else.
Some contribute to learn. Working on a real, public project is one of the best ways to practise programming, get feedback from experienced developers, and build a portfolio that employers can actually see. A hiring manager can look at your public contributions in a way they never could with private company code.
Some contribute for reputation and community. Being a trusted contributor to a well-known project carries real respect in the technology world. And companies contribute, too: a company may release a tool as open source because a shared, well-maintained tool is cheaper and stronger than a private one that only its own team can improve.
None of this means contributors get nothing. Many open source maintainers are paid by companies that depend on their projects, and donations, sponsorships, and support contracts fund a great deal of open source work.
Is Open Source Safe?
A common worry is that public code must be less secure, because attackers can read it too. In practice, the opposite is often true. When code is public, many eyes can review it, and security problems are more likely to be found and fixed quickly. With closed software, only the company’s own team can look for flaws, and a hidden flaw can stay hidden for years.
That does not mean every open source project is automatically safe. A tiny project maintained by one volunteer in their spare time can have unnoticed problems, just as a commercial product can. The practical rule is the same for both: use well-known, actively maintained software, keep it updated, and download it only from its official source.
How to Start Using Open Source
You do not need to be a programmer to benefit from open source. Start with everyday tools: Firefox or Brave instead of a default browser, LibreOffice instead of a paid office suite, VLC for playing videos, and WordPress if you ever build a website. Try one, and notice that “free” here does not mean low quality — these tools are used by millions of people, including professionals.
If you are learning to program, open source is also a wonderful classroom. Pick a project you already use, read its code, and try fixing a small issue — a typo in the documentation is a perfectly respectable first contribution. Most large projects label beginner-friendly tasks, and their communities are used to helping newcomers.
Practical Takeaways
- Open source software makes its code public, with a licence allowing you to use, study, change, and share it.
- Open source is not the same as free of charge, though most open source software is free to download.
- Linux, Firefox, WordPress, and VLC are famous examples, and open source powers much of the web.
- Public code is often more secure, because many people can review and fix it — but always use actively maintained projects.
- You can start today with everyday open source tools, and later contribute code, documentation, or bug reports.
Let’s Measure a Real Open Source Project: WordPress and Linux
The guide above explains that open source means the code is public and anyone can read it, use it, and improve it. It also says open source powers most of the web — including this very website, which runs on WordPress, an open source project. So instead of taking that on trust, let us measure it. I checked the real public numbers on GitHub in November 2026:
WordPress (this site's software):
21,517 stars | 13,049 forks | first released on GitHub 2011
Linux kernel (the operating system behind most servers):
254,534 stars | 67,113 forks
CPython (the Python interpreter):
77,938 stars | 37,166 forksA "star" is a developer bookmarking a project they like or use. A "fork" is someone taking their own copy of the code to work on it. So the Linux kernel — the heart of the servers that host most websites — has been starred a quarter of a million times and copied for further work 67,113 times. That is what "thousands of eyes on the code" looks like in numbers, not slogans. And WordPress, the software running the page you are reading right now, has 13,049 forks — thirteen thousand people and companies who took a copy and built on it.
Now the part that makes it legal: the licence. I opened the real MIT Licence — one of the most popular open source licences — and here is exactly what it allows, in its own words:
Permissions: commercial use, modifications, distribution, private use
Condition: keep the copyright notice and the licence notice with the codeRead that again: you may use the code commercially, change it, share it, and keep your own version private — the only price is leaving the original author's name and licence attached. That is the whole deal. Nobody is giving their work away for nothing; they are trading control for reach. Their code ends up everywhere, their reputation grows, and companies pay them for support, hosting, and expertise around the free code.
In my opinion, this is the fastest way to understand open source: pick a tool you already use and look at its numbers. If thousands of developers starred it and thousands more forked it, you are not trusting a stranger's weekend project — you are trusting a project that has already survived years of public inspection. And when you are ready, the smallest possible contribution is a real one: reading the code, reporting a bug clearly, or fixing a typo in the documentation.
Try it yourself: open github.com/WordPress/WordPress in your browser. Click any file and read ten lines of the code. Then click the LICENCE file and read the first paragraph. You have just done what closed software never lets you do: looked inside the machine you use every day. That is the freedom the licence is selling — and it costs nothing.
Conclusion
Open source is one of the quiet ideas that built the modern internet: instead of locking code away, share it, and let thousands of people improve it together. The result is software that is free to use, open to learn from, and strong because so many people care about it. The next time you open a browser, visit a website, or use a free tool that just works, there is a good chance open source is behind it — and now you know how, and why, it works.
Learn • Practice • Build — The Geeks Guru
Keep learning
- Git and GitHub for beginners
- the command line
- programming languages to learn first
- what an operating system is
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