Open source AI inference stack
Cairn is how we make the second one happen.
Mozilla and Mila are defining the interface contracts between every layer of the AI inference stack, so the parts can be changed by whoever runs them.
AI today is at a crossroads, where it could be closed and owned by a few, or open and available to every coder, developer, enterprise and nation.
Mark Surman, President, MozillaThe point
Swap any part. Keep the stack.
Most AI stacks are assembled by hand, and the application is the glue holding them together. Change the application and you rebuild everything behind it.
Cairn puts the contract at the boundary instead. The application becomes a client. That is what the contracts are for, and it is the part worth your attention.
Swap the engine
− model server + model server
Swap the hardware
− local GPU + remote cluster
Swap the gateway
− gateway + gateway
Three ways to read the same thing
If you build with AI
The contracts are published. Anything that satisfies one can replace what is there, with no integration code and no change to the rest of the stack.
If you run an organisation
The decision stops being all or nothing. Run every layer yourself, rent every layer, or draw the line where it suits you and move it later without rebuilding.
If sovereignty is your question
Who controls the stack decides who controls the data, the cost and the roadmap. Published contracts make that a choice rather than an inheritance.
Canada has a choice: depend on technologies developed elsewhere, or build more of what we need here at home. Open-source AI gives Canadian businesses and institutions greater control over their technology and data.
Hon. Evan Solomon, Minister of Artificial Intelligence and Digital InnovationWho is building it
By delivering an open, secure AI foundation layer, we empower organizations, from small businesses to non-profits to governments, to own their technological future so they can run, control, and maintain AI models themselves.
Valérie Pisano, President and CEO, MilaAnnounced at ALL IN in Montréal in September 2026, with an initial CAD 5 million commitment from Mozilla, CAD 1 million in year-one support from Hypertec for Canadian deployments on its infrastructure, and backing from the Government of Canada.
Hypertec is proud to help turn open source innovation into AI that Canadian organizations can deploy securely and under their own control.
Simon Ahdoot, CEO, Hypertec GroupReference
The architecture
Hover over or tap any layer or component to see what it does.
Status
Where this actually is
This is an alpha and it is not ready for you yet. We expect to open the code in the coming weeks.
We are publishing the architecture now because it has been the most useful thing we have to think with, and because we would rather be told what is wrong with it before the code lands than after.
What we want from you
Tell us what is wrong with this.
The architecture above is a position, not a conclusion. If a contract is in the wrong place, or a layer is missing, or your hardware breaks an assumption in it, that is the feedback worth having now.