Mojo's Compiler Is Now Open Source, but It Won't Take Outside Fixes Yet

Modular has published the source code for the compiler and toolchain of Mojo, its programming language for AI and high-performance computing, under the Apache 2.0 license with LLVM exceptions, the company said in a post dated Aug. 18.

"The source code for the Mojo compiler, tooling, and everything else you need to build the language are now available in our modular GitHub repository," the post states. The repository is at github.com/modular/modular. Apache 2.0 permits commercial use and modification, and the LLVM exceptions are the added terms the LLVM compiler project uses so that code produced by a compiler does not inherit the compiler's license conditions.

Publishing the code does not yet mean the project will merge outside changes to it. "As such, we aren't ready to take contributions to the compiler and tooling," the post says, adding that the company aims to accept them "by the end of this year." Mojo's standard library, a separate part of the codebase, has taken outside contributions since 2024, according to the post.

The release follows the language's 1.0 version. "Last week Mojo hit 1.0 (with source stability), and today we're excited to open source the entire compiler and toolchain," the post says. Source stability is a commitment that code written against the language will keep compiling as the language changes.

Modular is now owned by Qualcomm. The announcement page carries the copyright line "Modular Inc, A Qualcomm Company."