Patent Pledges and Open Source Software Development

For all its benefits, one aspect of open source software does cause headaches: understanding the legal terms that control its development and use. For starters, scores of licenses have been created that the Open Source Initiative recognizes as meeting the definition of an “open source license.” While the percentage of these licenses that are in wide use is small, there are significant and important differences between many of these popular licenses. Moreover, determining what rights are granted in some cases requires referring to what the community thinks they mean (rather than their actual text), and in others by the context in which the license is used.

In part as a result of this complex legal landscape, the founders of an open source project will sometimes use a mechanism in addition to an open source license when they want to provide additional or more specific rights relating to patents that may be infringed through the modification, distribution or use of code they contribute to project software. That mechanism is often referred to as a “patent pledge” or “patent non-assertion pledge,” and in the course of this blog entry I’ll try and explain why and when this mechanism may be used, and how the benefits it conveys relate, compare, and add to the rights provided under open source licenses.

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