Open source describes practices in production and development that promote access to the end product's source materials. Open source is a philosophy as well as a pragmatic methodology. Open source evolved with the rise of the Internet.

The opening the source code enabled a self-enhancing diversity of production models, communication paths, and interactive communities. Open source software describes the environment that the new copyright, licensing, domain, and consumer issues created.

A main principle and practice of open source software development is peer production by bartering and collaboration, with the end-product, source-material, "blueprints" and documentation available at no cost to the public.