Source code is the recipe
Most software arrives as a finished application. Open-source software also makes its human-readable instructions available. Developers can audit those instructions, propose fixes, or build a modified version.
The licence is the rulebook
Open source is a legal category. Licences such as GPL, MIT, and Apache 2.0 grant different permissions and impose different obligations. “Available on GitHub” is not automatically the same as open source.
| Licence | What it asks of you | Examples |
|---|---|---|
| MIT | Keep the copyright notice. Otherwise, do what you want. | jQuery, Rails, Swift |
| Apache 2.0 | MIT, plus patent grants, plus a notice file on changes. | Kubernetes, Android, TensorFlow |
| GPL v3 | If you distribute a modified version, share your changes under the same licence. | Linux kernel, GIMP, Bash |
| AGPL v3 | GPL, plus the same sharing rule applies to network use. | Nextcloud, Grafana, Mastodon |
| BSL / SSPL | Source-available, not open source. Used by some database companies. | MongoDB, CockroachDB |
Free software can still cost money
A project may charge for hosting, support, training, certification, or enterprise features. The freedom is about control and permission, not a promise that every service costs zero.
Community does not mean amateur
The Linux kernel, Kubernetes, PostgreSQL, and most of the modern web are developed in the open by a mix of volunteers and paid engineers from major companies.
The trade-off
You gain transparency, portability, and the ability to change suppliers. You may also take on more responsibility for integration, updates, support, and operational knowledge.
Open source gives you options. It does not remove the need to make good technical decisions. The Linux Institute team
How to think about an open-source project
Three signals matter:
- Backing. Is there a foundation, a company, or a critical mass of contributors keeping it alive?
- Cadence. Does the project publish releases on a predictable schedule, with notes about what changed?
- Adoption. Are governments, universities, or well-known companies running it in production?
If the answer to all three is yes, the project is probably a safer bet than the equivalent closed-source product — at zero licensing cost, and with the option to migrate away.