Mojo is now open source!

(modular.com)

78 points | by visheshdembla 3 hours ago ago

19 comments

  • SwellJoe 18 minutes ago

    As long as it was proprietary, I could ignore it. Now, I guess I have to learn a little something about it.

  • setopt an hour ago

    Very exciting. Closed source was one of the main things making me not try it out yet.

    Any good resources for getting started? And anything on doing NumPy/SciPy-like stuff in it?

  • mrbonner an hour ago

    So I think the permissive license like Apache 2 without opening up for upstream contributions would be the way of future open source development. In a very similar way of SQLite. It definitely will help shield off a bunch of AI generated contributions first and foremost and then, aligning mental model with the human contributions with Mojo leader team.

  • totalperspectiv 3 hours ago

    This is really exciting. I've been using Mojo off and on for side projects over the last two years.

    (copying from some previous Mojo threads) It's got an ownership system adjacent to Rust, comptime similar to Zig, and a first class dependent type system. Even more exciting, is that uses LLVM (to the best of my understanding) in some novel ways and for more optimizations.

    • dlahoda an hour ago

      Hm, in docs they say that dependent type system is not first class seems.

      Is it even dependent? More like refinement types, which seems will be in Rust too.Also HN recently mentioned Rust building similar llvm based integration with GPU.

      But compared with Python, Julia, Matlab, R, Rust, C, C++ - Mojo feel relief for working with numerics.

  • melodyogonna 2 hours ago

    Such an exciting time for Mojo, I don't think people realize just yet the innovation being brought to fore here.

  • melodyogonna 3 hours ago

    Related post with relevant pr: https://news.ycombinator.com/item?id=49347777

  • ChrisArchitect 3 hours ago
  • Lichtso 3 hours ago

    Technically soruce available now with the promise of accepting contributions (thus becoming fully open source) early next year. But since it is an Apache 2 license (like the rest of the LLVM project) you are already allowed to fork and contribute to your own fork right now, just no upstreaming.

    For many the closed source nature of the compiler was a knock-out criterion. We will see if Mojo can gain traction now or if it has missed its window of opportunity.

    • cube2222 2 hours ago

      It’s open source under the Apache 2 license, not source available.

      Accepting contributions is not required to be open source.

      SQLite doesn’t accept contributions from random people either [0] (though you could argue being public domain isn’t being open source).

      Anyway, this is great, I was waiting for this to take the language for a spin! Congrats to the Mojo team!

      [0]: https://simonwillison.net/2025/Dec/29/copyright-release/

    • SwellJoe 15 minutes ago

      You're just making up your own definitions of things.

      If the complete source is available and distributable under an OSI-approved license, it is absolutely Open Source. Accepting outside contributions is nowhere in the definition of Open Source.

    • fluffybucktsnek 2 hours ago

      Technically, the criteria for open source is freedom to freely distribute and modify the source code, not to upstream changes. That's a different for thing.

      https://opensource.org/osd