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Pure OCaml low-level git bindings
OCaml Makefile


Pure OCaml low-level bindings to Git -- Guaranteed no C inside.

Support for on-disk and in-memory Git stores. Can read and write all the Git objects: the usual blobs, trees, commits and tags but also the pack files, pack indexes and the index file (where the staging area lives).

All the objects share a consistent API, and convenience functions are provided to manipulate the different objects. For instance, it is possible to make a pack file position independent (as the Zlib compression might change the relative offsets between the packed objects), to generate pack indexes from pack files, or to expand the filesystem of a given commit.

The library comes with a command-line tool called ogit which shares a similar interface with git, but where all operations are mapped to the API exposed ocaml-git (and hence using only OCaml code).

The API documentation is available online.

Build Status

Build and Install Instructions

To build and install the project, simply run:

$ opam install git

What is supported

  • The loose object files can be read and written;

  • binary blobs (files)

  • trees (directories)
  • commits (revision history)

  • The pack files and pack indexes (which are collections of compressed loose objects using a diff-based representation) can be read and written). Moreover, diff hunks are exposed using a higher-level position-independent representation so that they can be manipulated more easily.

  • The index file (cache) -- used as for managing the stagging area -- is fully supported. Which means that git diff and git status will work as expected on a repository created by the library.

  • Basic support for client-side cloning and fetching (using bare and deepen options) but with no support for fancy download capabilities which is exposed by usual Git servers.

What is not supported

  • Only client-side operations are currently supported. Implementing the corresponding server-side implementation is high on the TODO list: using a dummy compression scheme, this should not be too hard to add, though.

  • Merging and rebasing strategies are not supported.


Performance is comparable to the git command. For instance, when downloading and processing a 5.4MiB pack file (the download time itself takes ~10s):

$ time ogit clone git://
Cloning into 'opam-repository' ...
Receiving data ... done.
Resolving deltas: 100% (37294/37294), done.
remote: Counting objects: 37294, done.
Checking out files: 100% (6527/6527), done.
HEAD is now at 267e08725291fc61b8411c0f20553ddd2e246d4f

real 0m22.522s
user 0m4.954s
sys  0m5.078s
$ time git clone git://
Cloning into 'opam-repository'...
remote: Reusing existing pack: 37868, done.
remote: Total 37868 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (37868/37868), 5.41 MiB | 408.00 KiB/s, done.
Resolving deltas: 100% (13973/13973), done.
Checking connectivity... done

real     0m17.409s
user     0m1.198s
sys  0m0.925s

Not much energy have been dedicated to profiling the protocol implementation yet, so there is still plenty room for improvement.

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