Open Source Initiative

The Open Source Initiative emerged in 1998 as an organization intended to give collaborative software development a practical public identity. Bruce Perens and Eric S. Raymond were among its founders, and the group helped popularize “open source” as language distinct from, though closely related to, the older free-software movement.¹ The term emphasized development methods, peer review, reliability, and business adoption while retaining legally enforceable freedoms to inspect, modify, and redistribute code.

OSI is not a software company, package repository, or programming community. Its role is chiefly institutional: it advocates for open-source principles, provides educational material, and serves as a recognized authority on whether licenses meet its definition.²

The Open Source Definition establishes the conditions that a license must satisfy to be recognized as open source. It requires free redistribution, access to source code, permission to create derived works, and the ability to distribute modified versions under the same general rights.²

The definition also bars discrimination against people, groups, fields of endeavor, or particular technologies. It permits license terms such as attribution, preservation of notices, and disclosure of modified versions, provided those terms do not undermine the basic freedoms. The definition describes licensing, not development style: a project may be open source whether it is produced by volunteers, a company, a government, or a mixed community.

OSI approval gives a license a recognized place in the open-source legal ecosystem, but it does not make the license universally suitable. OSI publishes a list of approved licenses and evaluates submissions through a public process involving license-review discussions and an appointed committee.³ Common approved licenses include the Apache License 2.0, GNU General Public License, MIT License, and BSD licenses, each of which allocates copyright, patent, attribution, and redistribution rights differently.

Approval is therefore a classification rather than a quality seal for the software itself. Developers and organizations still need to examine compatibility, patent provisions, notice obligations, contributor agreements, and the intended distribution model. Compliance depends on how a license is applied to particular code and products.

OSI’s most consequential work often concerns boundaries and terminology rather than famous software projects. Its definition distinguishes open-source licensing from merely allowing source-code inspection: a license must grant durable rights to modify and redistribute the work, not simply publish the code.²

The organization has also had to address newer license designs that retain some open-code features while adding restrictions aimed at cloud providers, resale, or particular uses. Such disputes show that “open source” is a defined licensing category, not a synonym for “publicly available” or “free of charge.” Another overlooked point is that OSI approval applies to license terms, while trademarks, patents, contributor agreements, data, and hosted services may create separate legal and practical constraints.

Open Source Definition

The ten-criterion standard used by OSI to determine whether a software license qualifies as open source.

OSI-approved license

A license that OSI has reviewed and accepted as conforming to the Open Source Definition.

Source code

The human-readable form of a program from which modified versions can be built.

Copyleft

A licensing approach that permits reuse while requiring certain redistributed derivative works to preserve comparable freedoms.