Modular Makes the MAX Source Available Under a New License That Bars Using It as Input to AI Reimplementations

Overview

Modular announced on October 22, 2026 that the complete MAX source code is now publicly available, released alongside a new MAX License. The company’s post describes the newly opened pieces, the graph compiler, runtime and hardware backends for CPUs and GPUs, as “source available”. The license text, last modified October 21, 2026, names the licensor as Modular Inc, a Qualcomm Company.

What Is Covered

According to Modular’s announcement, the release opens “the graph compiler, runtime, and hardware backends” and builds on earlier steps: the Mojo standard library in 2024, MAX’s kernels, models, serving infrastructure and APIs throughout 2025, and the full Mojo compiler and toolchain in August of this year. The Herald previously reported on the compiler release.

Not everything moves to the new license. Modular says that many MAX components, including the MAX kernel library in Mojo, Mojo interfaces for programming accelerators, Python APIs for the serving CLI and modeling, and MAX models, are already open source under Apache 2.0 and “will remain under Apache 2.0”. The new MAX License covers the internals released this week plus the MAX binaries Modular distributes, and each source file carries a header naming its license. The repository README says portions of the MAX source code and its binary distribution are licensed under the MAX License, with the remainder under Apache 2.0 with LLVM Exceptions.

What the License Allows

Modular’s post says users can build and distribute commercial products with MAX “without licensing fees or royalties”, and can fork MAX to contribute back to the main project. The license text grants a perpetual, worldwide, non-exclusive, no-charge, royalty-free license to reproduce and prepare derivative works and to distribute derivative works in object code form. It also says a derivative work may be licensed under terms of the licensee’s choosing, provided any portion of MAX it contains stays subject to the MAX License terms.

The Limits

The announcement lists three limitations, which the license text reflects in more detailed form.

AI-assisted reimplementation. The post states: “You can’t use any part of MAX as input to an AI system to produce a reimplementation of MAX.” The license clause says a licensee shall not use MAX “as training data, fine-tuning data, or input to any AI system in order to produce software that reimplements or substitutes for MAX”. The same clause adds: “This does not restrict using AI tools to read, analyze, improve, or explain MAX, or to develop Your own software that runs on or interoperates with MAX.”
Modified source. The post says: “You can’t publish or distribute modified MAX source code, except by forking MAX for the purpose of contributing changes back to the main project.” The license text separately allows publishing modified source in a fork of Modular’s official repository “to contribute to a Modular project”.
Hosted services. According to the post, anyone using MAX for hosted inference or training services sold to customers must prominently display the “Modular Accelerated” wordmark. The license text applies this to a legal entity that commercially deploys MAX as a hosted or managed AI training or inference service to other legal entities, and requires submitting materials bearing the marks to Modular for written approval before use.

The license also states that Modular and its affiliates may use usage and telemetry data “for any purpose”, and that Modular owns that data. The post adds that MAX may collect usage telemetry and that the software is provided as-is, without warranties.

Modular’s Stated Rationale

The company says the distribution restrictions are “designed to prevent fragmentation into incompatible versions of MAX, not to discourage individual developers from exploring new ideas”. It also expresses a hope “to replicate LLVM’s success of getting people to build on a shared codebase”. On the AI clause, it writes: “We want to build a community and pull people together, not be the foundation for many AI-driven forks.” The post also says: “we expect our approach to continue evolving as the technology matures and we hear more from the community.”

The OSI Definition for Reference

The Open Source Initiative’s Open Source Definition begins: “Open source doesn’t just mean access to the source code.” Among its criteria, number 4 says a license “may restrict source-code from being distributed in modified form only if the license allows the distribution of “patch files” with the source code for the purpose of modifying the program at build time”, and number 6 says a license “must not restrict anyone from making use of the program in a specific field of endeavor”. The Herald found no statement in the sources reviewed that the OSI has assessed the MAX License, and Modular’s own post uses the term “source available” for the newly opened components.

What Comes Next

Modular says it is opening MAX to community contributions starting immediately, initially accepting bug fixes, with plans to expand to refactors and other changes over time. It also plans an alliance program for hardware vendors, model labs and data center operators; partners that contribute engineering resources, compute or early model checkpoints would get “a voice in governance and conformance standards” and “more permissive licensing”, according to the post. A live Q&A with cofounders Chris Lattner and Tim Davis is scheduled for November 10 at 10 AM PT.

What We Don’t Know

The sources reviewed do not include independent legal analysis of the MAX License, and the announcement does not say how Modular would determine that a project counts as an AI-produced reimplementation of MAX. How the alliance partners’ “more permissive licensing” would differ from the public license has not been published in the sources reviewed.