BuildKit is a free toolkit for turning source code into build artifacts in a repeatable way. It consists of the buildkitd daemon and buildctl client, and uses LLB, a binary format for expressing process dependency graphs. Build definitions can come from Dockerfiles or other frontends that convert them to LLB. BuildKit supports concurrent dependency resolution, instruction caching, cache import and export, nested jobs, multiple output formats, and automatic garbage collection. It can run builds without root privileges and supports OCI (runc) and containerd worker backends. Results can be exported as images, local directories, tarballs, Docker tarballs, or OCI tarballs. The daemon exposes a gRPC API through a Unix socket by default, with TCP sockets also available. Binaries are listed for Linux, macOS, and Windows. The unofficial macOS Homebrew formula does not include buildkitd; the project gives Lima in a Linux virtual machine as one way to run it. BuildKit is licensed under Apache-2.0.
Who it is for
BuildKit suits developers and build-platform teams that need configurable, cache-aware artifact builds. Its frontends, worker backends, and output options are relevant to projects integrating build execution into their workflows.
What is good
- Supports concurrent dependency resolution and instruction caching.
- Imports and exports build caches.
- Can execute builds without root privileges.
- Exports images, directories, and several tarball formats.
- Binaries are listed for Linux, macOS, and Windows.
What to know first
- Unofficial Homebrew formula omits the buildkitd daemon.
- GitHub Actions, S3, and Azure Blob cache options are marked experimental.
Verdict
BuildKit provides a configurable build engine with multiple frontends, worker backends, and output formats. macOS users should note that the unofficial Homebrew formula does not include the daemon.
BuildKit plans and pricing
All plansCompared on container build tools
- Free plan
- Yes
