Mojo is Now Open Source

Modular has open-sourced the entire source code of the Mojo language, including its compiler, toolchain, and standard library, under the Apache 2.0 license (with LLVM exception).

Mojo is a general-purpose programming language designed to leverage advanced compute environments such as GPUs and AI accelerators. While it has been developed alongside the community for the past four years, the compiler remained closed-source. With this release, developers can now build the compiler from the GitHub repository and modify and test the standard library and kernel code using Bazel.

External contributions to the compiler and toolchain are not currently accepted, but contributions are planned to be accepted by the end of this year. The standard library has already been accepting contributions since 2024, and questions regarding the source code and project sharing are available through the official forum.