BuildKit vs Dagger

BuildKit is a free toolkit for turning source code into build artifacts. It consists of the buildkitd daemon and buildctl client, and uses LLB, a binary format for describing process dependency graphs. Builds can use Dockerfiles or other LLB-compatible frontends, resolve dependencies concurrently, cache instructions, import and export caches, run nested jobs, and collect unused data automatically. BuildKit supports execution without root privileges and OCI (runc) or containerd workers. Results can be exported as images, local directories, tarballs, Docker tarballs, or OCI tarballs. Cache options include inline, registry, local-directory, and GitHub Actions backends; the README marks GitHub Actions, S3, and Azure Blob options experimental. The daemon provides a gRPC API over a Unix socket by default, with TCP sockets also supported. Binaries are available for Linux, macOS, and Windows. The unofficial Homebrew formula for macOS omits buildkitd; the project gives Lima in a Linux virtual machine as one way to run it. BuildKit is licensed under Apache-2.0.

Dagger is a software stack for continuous integration built around an API, executable code, and a portable DAG execution engine. Pipeline logic can run locally or in Dagger Cloud, with automatic caching and end-to-end tracing. Cloud Checks connect a GitHub repository to Dagger Cloud and run checks on Cloud Engines after events such as pushes or pull requests, without a CI workflow file. Official modules cover testing, linting, formatting, type checking, browser tests, and Helm chart validation, and can be extended in a user's preferred language. The CLI has installation instructions for macOS, Linux, and Windows, and the documentation includes a self-hosting guide. Individual is free and allows one user, 1,000,000 monthly events, one month of run history, and community support. Team costs $50 a month after a two-week trial, for up to 10 users, 10,000,000 monthly events, one year of run history, and email support. Enterprise pricing is custom; SSO and managed single-tenant deployment are contact items. The site links to security and compliance information.