Definition
Open source software, usually shortened to OSS, is software whose underlying code is openly available for anyone to view, use, change, and contribute to. Most commercial software keeps its code secret, but open source software shares it openly, so anyone can see how it works, use it freely, build on it, and often help improve it. This openness has produced some of the most important and widely used software in the world, much of it built and maintained by communities of contributors rather than a single company.
Open source software matters because it underpins a vast amount of modern technology and represents a different way of building and sharing software, based on openness and community. This page explains what open source software is, how it works, why it became so important, how it differs from closed, proprietary software, and the realities of relying on it.
What open source software is
Open source software is software whose code is open for anyone to see and use. Rather than keeping the code secret, open source projects share it, allowing people to view how it works, use it, modify it, and often contribute improvements back.
It is defined by that openness. The code is available, usually freely, and the project is frequently built and maintained by a community of contributors rather than locked inside one company. This open, shared model is the essence of open source.
How open source software works
An open source project makes its code publicly available, often on a platform where anyone can view it, use it, and propose changes. People around the world can use the software freely, build on it, report problems, and contribute improvements that the project can accept.
Many open source projects are sustained by communities. Contributors who care about the software help maintain and improve it, and the open model means many eyes can examine the code and many hands can help. Some projects are backed by companies, but the openness and community participation are what define how they work.
Why open source became so important
Open source produces software that is free to use, transparent, and often very high quality, because many people can examine and improve it. That combination made it the foundation for an enormous amount of modern technology, with countless products built on open source components.
Its openness also builds trust and avoids lock-in. Because anyone can see the code, there are no hidden surprises, and because it is open, users are not trapped depending on a single company's whims. For developers especially, the ability to inspect, use, and build on software freely is hugely valuable.
Open source vs proprietary software
| Open source software | Proprietary software | |
|---|---|---|
| The code | Open for anyone to see | Kept secret |
| Use | Often free to use and build on | Usually paid and restricted |
| Built by | Often a community | Usually one company |
| Trust | Transparent, inspectable | You trust the company |
The realities of relying on open source
Open source is not automatically reliable or supported. Some projects are well-maintained, while others are kept going by a few volunteers and could be abandoned, so relying on open source means considering how healthy and active a project really is. Free does not mean guaranteed.
There are also responsibilities and questions around using it well, like understanding the terms a project is shared under and keeping components secure and up to date. Open source is powerful and valuable, but using it wisely means treating it as a real dependency, not a worry-free freebie.
How to use open source well
- Check that a project is healthy, active, and maintained before relying on it.
- Understand the terms the software is shared under.
- Keep open source components secure and up to date.
- Consider contributing back to projects you depend on.
- Treat open source as a real dependency, not a worry-free freebie.
Helping open source projects grow
Open source projects live and die by community: people discovering them, trying them, trusting them, and contributing. That makes content and clear communication essential, since a project no one knows about or understands will not attract users or contributors.
Infrasity helps open source projects and the companies behind them tell their story clearly, with documentation and content that help developers discover, understand, and adopt them. For open source, where adoption is everything, being genuinely clear and visible is what drives growth.
Frequently Asked Questions
What is open source software?
It is software whose underlying code is openly available for anyone to view, use, change, and contribute to, rather than kept secret. It is often free to use and built or maintained by a community of contributors, and it underpins a vast amount of modern technology.
How is open source different from proprietary software?
Open source software has code anyone can see, is often free to use and build on, and is frequently built by a community. Proprietary software keeps its code secret, is usually paid and restricted, and is made by one company. Open source is transparent, while proprietary asks you to trust the company.
What should you consider when relying on open source?
How healthy, active, and maintained the project is, since some are well-supported and others could be abandoned. You should also understand the terms it is shared under and keep components secure and up to date. Open source is valuable but should be treated as a real dependency.
Related terms
OSS Launch Visibility, GitHub Repositories, Developer Community, Developer Marketing (B2D), Bottom-Up Adoption