lfortran

What LFortran is

LFortran is described as a modern open-source interactive Fortran compiler built on top of LLVM. The README says it can execute a user's code interactively to allow exploratory work much like Python, MATLAB, or Julia, while also compiling to binaries with the goal of running on modern architectures such as multi-core CPUs and GPUs. The project points to a website at lfortran.org and offers an online try-it environment at dev.lfortran.org. It also links a JupyterLite notebook so users can experiment in a browser without a local install. The documentation, installation instructions, motivation, and design are said to live at docs.lfortran.org, and that site is generated from files in the doc directory of the repository. The README presents LFortran as the official main repository for the compiler, and it asks users to send pull requests and open issues there. Development moved from GitLab to GitHub on July 18, 2022, according to the README, and the project welcomes contributions. The compiler is positioned for both interactive use and ahead-of-time compilation, which the README frames as useful for exploratory numerical work as well as for producing binaries that target current hardware. The interactive mode is the feature that most distinguishes it from traditional Fortran toolchains that only compile. By letting users execute snippets and inspect results without a separate build step, the tool fits exploratory numerical work, and the same source can later be compiled to a binary when the user is ready to target real hardware.

Community and funding

The README describes an active community around the project. A main mailing list is hosted at groups.io, and the project invites chat on Zulip through a join chat badge. The development section points contributors to a CONTRIBUTING document for more information on how to help. The donations section explains that LFortran development can be supported through NumFOCUS or Open Collective as well as GitHub Sponsors, with links provided for each. The README states that all donations are used strictly to fund LFortran development, citing tasks such as paying developers to implement features, running sprints, improving documentation, and fixing bugs. It adds that donations to LFortran are managed by the NumFOCUS foundation, a 501(c)(3) non-profit, so contributions may be tax-deductible for those subject to US tax law. For other funding or help discussions, the README invites contact with Ondrej Certik at the listed email. The project also shows a star history chart so visitors can see growth over time. Taken together, the README presents LFortran as a community-driven compiler with non-profit backing rather than a single-vendor product, and it stresses that contributor pull requests and issue reports are the main path for changes. The README points to a CONTRIBUTING document for the details and to the documentation site for motivation and design, and it notes the main mailing list and Zulip chat as places to ask questions. The project also shows a star history chart so visitors can see how the community has grown, and it presents donations through NumFOCUS and Open Collective as a way to fund continued development.

Getting involved

The README keeps the contribution path simple and direct. It welcomes all contributions and directs readers to the GitHub repository as the main development location, asking them to send pull requests and open issues there. The CONTRIBUTING document is referenced for the details of how to participate, and the mailing list plus Zulip chat are offered for discussion. Because the project moved from GitLab to GitHub in July 2022, the README makes a point of telling users where the current canonical repository lives so they do not open issues in the wrong place. The documentation site is presented as the place to learn the motivation and design, and the doc directory in the repository is the source for that site. The donation links round out the getting-involved picture by giving users who cannot contribute code a way to fund development instead. The README does not include a build tutorial or a feature list in the text itself, instead pointing outward to the documentation site for installation and design notes. This means a new user learns the compiler's capabilities and build steps from docs.lfortran.org rather than from the README body, and the README's job is to orient the visitor, state the license and interactive nature, and route them to the right places for code, chat, and funding.

Editorial conclusion

LFortran is distributed under a BSD license, and the repository's most recent commit was on 2026-08-26. The project is hosted at github.com/lfortran/lfortran.