Installing Buck2

The latest set of buck2 executables can be found under the latest release page.

Additionally, for each bi-monthly release there is a dotslash file that is appropriate for committing to a repository. This will automatically fetch the correct version and architecture for each user, and ensures a consistent build environment for each commit in the repo.

If no prebuilt binary is available for your platform — or you want to hack on Buck2 itself — see Building from Source below.

Building from Source

Buck2 currently requires a nightly Rust toolchain. The simplest setup is via rustup, which provisions the right rustc/cargo for you. Once it's installed, build and install buck2 directly from GitHub:

rustup install nightly-2026-02-28
cargo +nightly-2026-02-28 install --git https://github.com/facebook/buck2.git buck2

This installs buck2 into a suitable directory such as $HOME/.cargo/bin, which you should add to your $PATH:

Linux / macOS

export PATH=$HOME/.cargo/bin:$PATH

Windows Powershell

$Env:PATH += ";$HOME\.cargo\bin"

Verify the install with buck2 --help.

To hack on Buck2, build from a clone of the repo instead:

git clone https://github.com/facebook/buck2.git
cd buck2/
cargo install --path=app/buck2

Using Nix

Most Nix users provision tools directly with Nix itself, rather than rustup. The Buck2 source ships a flake.nix that exposes a cargo/rustc development shell:

git clone https://github.com/facebook/buck2.git
cd buck2/
nix develop . # add 'rustc' and 'cargo' to $PATH
cargo build --release --bin=buck2

A Nix package (e.g. nix build .#buck2) does not yet exist; see buck2 in nixpkgs for inspiration for writing one. An .envrc using the Nix flake is provided for direnv users — direnv allow will give a usable development environment.

`protoc` on non-Tier-1 platforms

Buck2 uses Protocol Buffers extensively, both internally and to talk to remote systems for things like Remote Execution. Compiling the .proto files needs the protoc compiler.

On Linux (aarch64/x86_64), Windows, and macOS the cargo build pulls a prebuilt protoc from the protoc-bin-vendored crate, so no setup is required.

On other operating systems, install protoc from another source (out of scope here) and point the build at it before running cargo build:

BUCK2_BUILD_PROTOC — path to the protoc binary
BUCK2_BUILD_PROTOC_INCLUDE — path to the protocol buffers header directory

For example, with protobuf installed under /opt/protobuf:

export BUCK2_BUILD_PROTOC=/opt/protobuf/bin/protoc
export BUCK2_BUILD_PROTOC_INCLUDE=/opt/protobuf/include

Building Buck2 with Buck2

See Bootstrapping for details. The gist:

reindeer --third-party-dir shim/third-party/rust buckify
buck2 build //:buck2