Open source gets thrown around a lot as a buzzword. Here's what it actually means and why I think it's one of the most important things in tech.
What it means
Open source software is software where the source code is publicly available. Anyone can read it, modify it, and usually redistribute it, subject to the terms of whichever licence it uses. The opposite is proprietary software — where the code is kept private and you're only given the compiled binary to run.
Why it matters — the trust angle
With closed source software you have no idea what it's actually doing. You're trusting the company that made it. With open source, anyone can look at the code and verify what it does. Security researchers can audit it. You can check yourself if something looks wrong. That transparency is genuinely valuable, especially for software that handles sensitive data or runs on infrastructure you care about.
The community effect
Good open source projects have communities around them — people filing bug reports, contributing fixes, writing documentation, answering questions. This makes the software better faster than any single company's engineering team usually can. PostgreSQL has been developed by a global community for decades. It's extraordinarily good, largely because of that model.
What it's given me personally
Almost everything I've learned has come from reading open source code. When you can look at how something actually works — not just the API documentation but the actual implementation — you learn at a completely different level. Open source is a massive library of worked examples from people who are often very good at what they do.
It's also meant that I've been able to build things that would be impossible otherwise. Pterodactyl alone would cost hundreds of thousands to build from scratch commercially. Because it's open source, I can run it, modify it, build on top of it. That's the gift the open source ecosystem has given to self-builders everywhere.
The licence stuff matters
Not all open source is the same — licences vary from very permissive (MIT, Apache) to more restrictive (GPL, which requires that derivatives are also open source). Worth understanding the licence of anything you're building on top of, especially commercially. But that's a detail; the principle — code should be readable, auditable, and improvable by anyone — is the important thing.