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Dune is a build system for OCaml. It provides a consistent experience and takescare of the low-level details of OCaml compilation. You need only to provide adescription of your project, and Dune will do the rest.

Dune implements a scheme that's inspired from the one used inside Jane Streetand adapted to the open source world. It has matured over a long time and isused daily by hundreds of developers, meaning it's highly tested and productive.

Dune comes with amanual. If you want to get started without readingtoo much, look at thequick start guide or watchthisintroduction video.

Theexample directory contains examples of projects using Dune.

Dune reads project metadata fromdune files, which are static files with asimple S-expression syntax. It uses this information to setup build rules,generate configuration files for development tools such asMerlin,handle installation, etc.

Dune itself is fast, has very little overhead, and supports parallel builds onall platforms. It has no system dependencies. OCaml is all you need to buildDune and packages using Dune.

In particular, one can install OCaml on Windows with a binary installer and thenuse only the Windows Console to build Dune and packages using Dune.

Dune is composable, meaning that multiple Dune projects can be arrangedtogether, leading to a single build that Dune knows how to execute. This allowsfor monorepos of projects.

Dune makes simultaneous development on multiple packages a trivial task.

Dune knows how to handle repositories containing several packages. When buildingviaopam, it is able to correctly use libraries that were previouslyinstalled, even if they are already present in the source tree.

The magic invocation is:

$ dune build --only-packages<package-name> @install

Dune can build a given source code repository against several configurationssimultaneously. This helps maintaining packages across several versions ofOCaml, as you can test them all at once without hassle.

In particular, this makes it easy to handlecross-compilation. This feature requiresopam.

Dune requires OCaml version 4.08.0 to build itself and can build OCaml projectsusing OCaml 4.02.3 or greater.

We recommended installing Dune via theopam package manager:

$ opam install dune

If you are new to opam, make sure to runeval $(opam config env) to makedune available in yourPATH. Thedune binary is self-contained andrelocatable, so you can safely copy it somewhere else to make it permanentlyavailable.

You can also build it manually with:

$ make release$ make install

If you do not havemake, you can do the following:

$ ocaml boot/bootstrap.ml$ ./dune.exe build -p dune --profile dune-bootstrap$ ./dune.exe install dune

The first command builds thedune.exe binary. The second builds the additionalfiles installed by Dune, such as theman pages, and the last simply installsall of that on the system.

Please note: unless you ran the optional./configure script, you cansimply copydune.exe anywhere and it will just work.dune is fullyrelocatable and discovers its environment at runtime rather than hard-coding itat compilation time.

If you have questions about Dune, you can send an email toocaml-core@googlegroups.com oropen a ticket on GitHub.

Dune was formerly known as Jbuilder. Migration from Jbuilder to Dune isdescribed in themanual.

Dune is fairly stable and used by the majority of packages on opam. Note thatDune retains backward compatibility with Jbuilder, and in particular, existingJbuilder projects will continue to be buildable with Dune.