The part I care about isn’t the license text, it’s what I can do on a laptop in a marina with bad wifi. The whole compiler and toolchain are in the modular GitHub repo — one clone, one bazelw command, builds against a local hello.mojo. Apache 2.0 with LLVM exceptions means I can ship binaries out of it without lawyering.
The catch worth planning around: they aren’t taking compiler or tooling contributions yet, aiming for end of year. So this is read-and-build access, not upstream access. My move is the cheap one — clone it, use —config=prebuilt-mojo to skip the full compile, poke at it, and see whether anything here is worth pointing at GPU work later. File the patch idea, don’t write it yet.
The story — Modular announced on August 18, 2026 that Mojo is fully open source under Apache 2.0 with LLVM exceptions, publishing the compiler, tooling, and everything needed to build the language in its modular GitHub repository. Mojo hit 1.0 with source stability the prior week. The standard library opened earlier and has taken contributions since 2024, but Modular isn’t ready for compiler contributions and aims to accept them by year’s end. (Source)