Open source means the source code needed to build/compile/run Mojo programs is available under a license that permits anyone to freely use/modify/share the code for any purpose, a la https://opensource.org/osd
Modular, the creator of https://en.wikipedia.org/wiki/Mojo_(programming_language) has stated many times that the language would eventually be open source, but they cannot give a timeline, for example:
https://www.modular.com/pricing#:~:text=Will%20Mojo%20ever%20be%20fully%20open%20source%3F
https://www.youtube.com/watch?v=tYujSI_aoqk&lc=Ugy-QQjJ4PYNJyrRc354AaABAg.A7Wv5n61lVtA7j_dibRIk7
Core modules from the Mojo standard library have been open sourced as of March 2024 https://www.modular.com/blog/the-next-big-step-in-mojo-open-source about a year after Mojo was publicly announced. This question is about when the rest of the language implementation needed to run Mojo program is open source.
If Mojo is not open source by the end of last year option, this question will resolve to "other".
1,000https://www.youtube.com/watch?v=XYzp5rzlXqM&t=842s says by the end of 2026, possibly earlier.
I asked a LLM to analyze the relevant repo for signs of preparation for open sourcing. Here's the result. The progress documented in changelog and changelog-released, while in hindsight obvious places to look, I had not seen.
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There are several clear indications in the modular/modular repository that point to preparation for open sourcing Mojo and its components, particularly the standard library:
1. Explicit Open Source Commitment in Documentation
- The FAQ under mojo/docs/faq.md states: "We have committed to open-sourcing Mojo in 2026. Mojo is still young, so we will continue to incubate it within Modular until more of its internal architecture is fleshed out."
- There is a rationale provided for not developing Mojo in the open from the beginning, referencing other successful staged-open projects like LLVM and Swift.
- See: [mojo/docs/faq.md](https://github.com/modular/modular/blob/main/mojo/docs/faq.md)
2. Standard Library Open Sourcing and Roadmap
- The standard library FAQ (`mojo/stdlib/docs/faq.md`) details that some modules are not yet open-sourced due to rapid change, tight integration, or proprietary aspects, but that the intent is to move most closed-source modules into the open-source repo over time.
- See: [mojo/stdlib/docs/faq.md](https://github.com/modular/modular/blob/main/mojo/stdlib/docs/faq.md)
3. Contribution Guidelines for Open Source
- mojo/CONTRIBUTING.md provides extensive guidance for prospective contributors, including:
- How to submit bugs, docs, and code.
- Clear "Accepting open source PRs" sections, with lists of what changes are accepted and avoided.
- A proposals process inspired by other open-source projects.
- Enforcement of the Developer Certificate of Origin, requiring that contributors agree to open-source licensing for their patches.
- See: [mojo/CONTRIBUTING.md](https://github.com/modular/modular/blob/main/mojo/CONTRIBUTING.md)
4. Changelog Mentions Open Sourcing
- The changelog (`mojo/docs/changelog.md`) includes entries explicitly stating that parts of the Kernel library and other packages "continue to be progressively open sourced."
- See: [mojo/docs/changelog.md](https://github.com/modular/modular/blob/main/mojo/docs/changelog.md)
5. Open Source Licenses
- The root LICENSE file and individual source files use the Apache License v2.0 with LLVM Exceptions, which is a standard open source license.
- See: [LICENSE](https://github.com/modular/modular/blob/main/LICENSE)
6. Community and Process Infrastructure
- There are dedicated community resources, a Code of Conduct, and references to Discord and forums for community engagement.
- The README and contributing guidelines direct users to these resources and outline the process for suggesting and submitting changes.
- See: [README.md](https://github.com/modular/modular/blob/main/README.md)
7. Process for Proposals and RFCs
- The proposals process is documented and encourages community input for significant changes, similar to other mature open-source projects.
- See: [mojo/CONTRIBUTING.md](https://github.com/modular/modular/blob/main/mojo/CONTRIBUTING.md)
Summary:
The modular/modular repository is structured and documented in a way that clearly anticipates and supports open source development, especially for the Mojo standard library. There is an active effort to move more components into the open, and the policies, processes, and license structure are all geared toward an open-source future. For details or to track progress, see the [modular/modular repo on GitHub](https://github.com/modular/modular).
Note: These results are based on a code search and may be incomplete. To view all results or search further, visit the [GitHub code search for modular/modular](https://github.com/modular/modular/search?q=open+source).