Open Source
Free code anyone can use
TL;DR
Software where the code is public and free. Anyone can use it, modify it, and learn from it. Most of the internet runs on it.
The Plain English Version
Imagine if Coca-Cola published their secret recipe and said "here, anyone can make this. Modify it if you want. Just don't say it's the original." That's open source, but for software.
When code is open source, it means anyone can see the source code, use it for free, modify it, and share their modifications. It sounds crazy from a business perspective, but it's how most of the internet works. Linux (runs most servers), WordPress (runs 40% of websites), Python (the most popular programming language), React (powers Facebook, Instagram, Netflix) — all open source.
Why would anyone give away code for free? Because open source creates ecosystems. Thousands of developers improve the code, find bugs, and add features — for free. The companies behind open source projects make money through hosting, support, and premium features.
Why Should You Care?
Because as a builder, open source is your superpower. Need a database? PostgreSQL is free. Need authentication? Dozens of open source options. Need a framework? Pick one. You're standing on the shoulders of millions of developers who shared their work. Learning to find and use open source tools is one of the most valuable skills in tech.
The Nerd Version (if you dare)
Open source licenses (MIT, Apache 2.0, GPL, BSD) define how code can be used, modified, and distributed. GitHub hosts most open source projects. Business models include open core (free base + paid features), SaaS (hosted open source), support/consulting, and dual licensing. The Open Source Initiative (OSI) maintains the official definition. Key orgs: Linux Foundation, Apache Foundation, CNCF.
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