Mojo is now open source (modular.com)

289 points by visheshdembla 2 days ago

andsoitis a day ago

Love this intentionality: ” Our open source approach has been deliberate: we’ve found that small and tight-knit design teams (not committees) are the best for finding the “soul” of a language, but that feedback from a broader community is essential to escape an echo chamber. As such, we first open-sourced the Mojo standard library, then released hundreds of thousands of lines of kernel code written in Mojo, tools, and support. We built together with community feedback and public design proposals, and are now open sourcing the compiler. We will continue to open our processes further as Mojo keeps maturing.”

eatonphil 5 hours ago

I did a review of Mojo a few months ago focused on Python compatibility if anyone's curious about that angle. Admittedly it is a narrow angle. I want to take another look at Mojo sometime not focused on Python.

https://theconsensus.dev/p/2026/03/12/mojos-not-yet-python.h...

melodyogonna 2 days ago

One of my favourite features of Mojo is linear types and how deeply they have been integrated into manual memory management - see:https://x.com/melodyogonna/status/2085089269484343725?s=20. When I first learned about linear types, my first thought of the use case was making manual allocations and deallocations safer without sacrificing usability, but I didn't know what that could look like; now I do. This is great because in Mojo, pointers are surfaced a lot more than in, say, Rust, but such sharp tooling in a language you expect to be safe by default can be problematic. Linear types, combined with the origin system, give the language a lot of flexibility; it is like using a sharp tool with a safety glove: the tool isn't any less sharp, but the chances of accidentally injuring yourself are reduced.

dang 6 hours ago

Recent and related:

Mojo 1.0 - https://news.ycombinator.com/item?id=49261128 - Aug 2026 (244 comments)

WalterGR 5 hours ago

From yesterday:

The Mojo language (by Modular, now Qualcomm) is now open-source - https://news.ycombinator.com/item?id=49358327 - 108 comments

branko_d a day ago

Is this a case of of Qualcomm commoditizing their complements? Does Mojo have a potential for disrupting Nvidia's current market position?

https://www.joelonsoftware.com/2002/06/12/strategy-letter-v/

melodyogonna 4 hours ago

I think people underestimate the fact that Nvidia's GPUs are really good. Modular/Qualcomm's stack will provide a lot more optionality, but from what I saw in the Modcon conference on Tuesday, most of the target audience is towards other hardware vendors. At the moment, after designing a new hardware, you'd have to also build the entire software stack already existing on Cuda, ROCm, etc - this can double or triple your hardware bring up time. If you plug into Max (not Mojo), you get most of the software stack for free, so your software bring up time can go from months of engineering hours to probably weeks.

mrbonner 2 days 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.

SwellJoe 2 days ago

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

embedding-shape 4 hours ago

Finally, gonna be a lot of fun to finally play around with, lets see how it compares to Python for ML ultimately :) The build process is quite heavy, pinning all my cores at 100% on a Threadripper 9970X for ~15 minutes which isn't so common.

Curious to know what setups they've tested Mojo on so far, as I understood it to be mainly for ML/AI stuff, so commonly pretty beefy workstation, yet I'm getting warnings that it's not recognizing my GPU (RTX Pro 6000). Seems easy enough to work around by editing the gpu_mapping in MODULE.bazel so I guess isn't a huge issue. Just strange to see a really CPU-heavy build, then not recognizing a somewhat common "prosumer" GPU (common in the ecosystem and expected user audience at least).

spmurrayzzz 3 hours ago

My expectation is always that sm120 is the forgotten orphan in the mix and that I'll have to monkey-patch my way to getting things running (and its not always due to lack of tcgen05 or other "real blackwell" features, its often just failing fallback kernel paths doing things that were clearly not tested).

Mojo's design goals would in theory help this problem long term, but my sm120 PTSD still lingers.

totalperspectiv 2 days 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 2 days 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.

jondea a day ago

I don't agree at all with your last paragraph. MATLAB and Julia are lovely for numerics, maths is terse and looks like maths! Mojo is hobbled by choosing Python style syntax, which does not lend itself well to maths.

WRT the type system, I agree MATLAB is a mess but Julia's multiple dispatch feels more like maths than any other language I've tried.

ainch 5 hours ago

Archit3ch a day ago

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

Out of those, Julia is the only one that combines Multiple Dispatch and native code, both important for numerics.

melodyogonna 2 hours ago

setopt 2 days 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?

totalperspectiv 2 days ago

https://mojolang.org is the best spot for getting started generally. numojo is the closest thing to numpy right now. You can check out more packages here: https://github.com/modular/modular-community/tree/main/recip...

MohamedMabrouk 2 days ago

NuMojo is the closest thing in the ecosystem to numpy and the final aim is offer numpy-like experience. https://github.com/Mojo-Numerics-and-Algorithms-group/NuMojo

vovavili 2 days ago

Can't you just use Numpy directly in Mojo?

MohamedMabrouk 2 days ago

Alien1Being 5 hours ago

"Qualcomm to Acquire Modular 06/24/2026"

https://investor.qualcomm.com/news-events/press-releases/new...

Can acqui-death be far away...?

ipsum2 3 hours ago

Prediction: Chris Lattner will be off chasing some other shiny thing within a year. Without a strong champion, the company will be subsumed into Qualcomm and stop publishing meaningful updates.

melodyogonna 3 hours ago

Chris Lattner is now Qualcomm's VP of AI Software and Tooling, so he is now responsible for all of Qualcomms AI software. Mojo wouldn't be doing any dying

melodyogonna 2 days ago

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

vovavili 2 days ago

The innovative potential of Mojo would be constrained to relatively niche and senior dev circles until they get a Windows release, which probably won't happen anytime soon. Python keeps the throne for now.

melodyogonna 2 days ago

I don't understand this premise. And the more I think about it, the less sense it makes. On the grand scale of things, Windows is the niche platform here. For consumer desktop use cases, it is king, but nobody deploys on it for the use cases that the first version of Mojo is optimised for.

andsoitis a day ago

pjmlp a day ago

Conscat 2 days ago

In the category of AI/HPC software Mojo aims to displace (which is my industry), I don't know many people who care that much about running Windows. The software I work on may only run as a Docker image or directly in a Linux/WSL. Mojo is hardly the only tool in the space (currently) lacking Windows support.

vovavili 2 days ago

solarkraft 2 days ago

The niche is so big that Microsoft invented WSL to run Linux programs on Windows.

pjmlp a day ago

dloss 2 days ago

They announced a partnership with Microsoft today.

vovavili 2 days ago

pjmlp 2 days ago

And Julia as well.

rirze 2 days ago

ChrisArchitect 2 days ago

pmkary 5 hours ago

What a beautiful standard library btw. Much to learn and take from.

ModernMech 2 days ago

"Modular Confidential (obviously), May 14, 2022"

lol, feels like espionage

https://github.com/modular/modular/blob/main/KGEN/docs/Desig...

Compiler walkthrough

https://github.com/modular/modular/blob/main/KGEN/docs/MojoC...

melodyogonna 2 days ago

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

Lichtso 2 days 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 days 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/

roundabout-host 2 days ago

Maybe it is not listed by the OSI, but it is 'open source' in practice, if the source is also in the public domain. The FSF's definition of free software makes more sense not only ideologically, but also because it does not try to be exhaustive.

lukaslalinsky 5 hours ago

SwellJoe 2 days 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 days 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