What is open source software?

What it means

Source code is the set of instructions a programmer writes to make a program work. With open source software, that code is public, and the license grants you permission to run the program, read how it works, modify it and pass it on. Well-known licenses include the GPL and the MIT license.

Open source projects have maintainers, and many have companies behind them. Linux and Docker are common examples. The other model is closed source software.

Why it matters to a business

• No license fee for the software: you usually pay nothing per user or per server for the program itself, though you still pay for hardware and for people. Some projects also sell a paid edition with extra features or support.
• No single vendor to lose: because the code is public, others can carry a project on if the company behind it changes direction or closes.
• Code you can read and change: your team or partner can audit it and adapt it, which a closed product rarely allows.
• Someone still has to run it: installing, securing, updating and supporting it costs time or money. Support can be bought from the vendor or from a service company.

How this shows up in our work

Most of the platforms we build for clients are open source: Linux, Kubernetes on Talos Linux, Proxmox VE, Ceph, Docker and OPNsense firewalls. Our FreePBX phone systems carry no per-seat license from us. We run Proxmox and Ceph for our own infrastructure, and we maintain public open-source tools of our own.

Learn more

• Open-source software on WikipediaA neutral overview of the idea and its history, useful for readers new to the topic.
• The Open Source DefinitionThe criteria a license must meet to count as open source, for readers who want the precise rules.
• Choose a LicensePlain summaries of common licenses, helpful for businesses publishing their own code.