Open source licensing revolutionized software development, creating a thriving ecosystem built on shared innovation and collaboration. Licenses like MIT and Apache-2.0 gave developers a standard, legally robust way to share code, reducing friction and accelerating adoption.
Today, we stand at a similar inflection point with open AI models. These models, increasingly foundational to research and industry, lack an equivalent licensing standard. Existing open source software licenses weren’t designed with AI models in mind, while most model-specific licenses are either too complex, overly restrictive, or legally ambiguous.
To fully unlock the potential of open AI, we need a license purpose-built for the realities of machine learning. That’s where OpenMDW comes in.
AI models differ fundamentally from traditional software. They are:
This complexity has led to a proliferation of bespoke, incompatible licenses that often:
The result? Friction in open ecosystems, legal ambiguity, and a significant barrier to collaboration and innovation.
OpenMDW, short for Open Model, Data and Weights License was born out of the effort to implement the Model Openness Framework (MOF). The MOF is a 3-tier classification system that defines what it means for a model to be truly “open”— not just available with limitations or use restrictions, but licensed openly across its code, architecture, parameters, training data, and documentation.
To make MOF practical, model developers needed a simple, standard license they could drop into any repository, just like Apache-2.0 or MIT is used in software. Something purpose-built for many types of content including models, not just code.
OpenMDW is the first truly permissive license designed from the ground up for machine learning models. Here’s what sets it apart:
It’s designed to apply to all components of a model release:
Importantly, OpenMDW does not require inclusion of all components. It applies only to what is distributed, while remaining compatible with many other licenses that may govern certain parts of the repository.
(OpenMDW users will of course have to continue to comply with any other third-party licenses that apply to other pre-existing materials in their repos, such as by providing license text and notices, source code where applicable, etc.)
OpenMDW grants expansive permissions including under copyright, patent, database, and trade secret law, a broad legal spectrum of rights relevant to AI artifacts.
It also includes:
Model Materials under OpenMDW include:
This comprehensive scope maps directly to the Model Openness Framework (MOF), ensuring that all critical elements of a model are covered if they are included with the distribution.
The Model Materials are not intended to be a requirement of what has to be included in the distribution. It only specifies that what is included in the distribution is covered by the license, and excludes anything covered by other licenses in the distribution.
OpenMDW grants broad rights to “deal in the Model Materials without restriction,” including for example:
These rights are granted free of charge, with no field-of-use restrictions, removing ambiguity for developers and enterprises alike.
OpenMDW imposes only minimal obligations:
There are no copyleft or share-alike conditions, meaning derivative models and integrations can remain fully permissive. This allows for maximum reuse and interoperability.
To prevent misuse of the commons, OpenMDW includes a patent-litigation termination clause: if a licensee initiates offensive patent litigation over the Model Materials, their license is revoked.
This mirrors best practices in open source software and helps preserve a collaborative ecosystem.
A major innovation: outputs generated by using a model under OpenMDW are completely free of licensing restrictions imposed by the provider of the Model Materials.
This eliminates confusion over whether generated text, images, code or predictions are encumbered by the model provider— a common point of uncertainty in existing licenses.
Adopting OpenMDW is straightforward:
The AI community is reaching an inflection point. Open models from AI2’s Molmo to Mistral, and open reasoning models like DeepSeek’s R1 to multimodal agents are reshaping what’s possible in the open. But their licensing status remains hard to characterize, since software licenses may not map cleanly onto AI models.
Some open weights models which use restrictive licenses have become gradually more permissive; but without a strong legal framework available for licensing, model producers have been forced to err towards the side of caution in designing their own licenses.
In his recent post, Nathan Lambert of AI2 rightly notes: “One of the long standing todo items for open-source AI is better licenses”, OpenMDW helps to fill that need.
Just as Apache-2.0 and MIT became foundational licenses for open source software, OpenMDW is positioned to become the standard for open models. Its clarity, scope, and permissiveness lower barriers for developers and create certainty for companies and researchers looking to build responsibly on open foundations.
This isn’t just about legal clarity, it’s about enabling an innovation-rich and open source AI ecosystem.
Visit openmdw.ai for more details including the FAQ.