Buck2 vs moon
Buck2
buck2.build
moon
moonrepo.devSide by side
| Figure | Buck2 | moon |
|---|---|---|
| Price from | Free | — |
| Free plan | Yes | — |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 1 | 0 |
| Spec score · Build Automation Software | 8.1 (#12) | 7.4 (#29) |
| Spec score · Monorepo Management Tools | 8.0 (#13) | 7.3 (#26) |
| Languages | The language support table lists C/C++, Erlang, Go, Haskell, Java, Kotlin, OCaml, Python, and Rust with available prelude rules; support usability varies by language. | The documentation lists full toolchain support for Bun, Deno, Node.js, Go, and Rust, with experimental support for Python and Ruby. |
| Purpose | Buck2 is a large-scale, fast, hermetic, multi-language build system and the successor to Buck. | moon is a repository management, organization, orchestration, and notification tool for web ecosystem codebases. |
| Support | The project directs users to report issues through GitHub and provides a community Discord server. | The official site links to GitHub and Discord for support. |
Plans
In their own words
Buck2
Buck2 is a free build system from Meta for large-scale repositories that combine multiple programming languages. It uses Starlark rules, a dynamic dependency graph, and incremental actions to support extensible builds. Its language table lists prelude rules for C/C++, Erlang, Go, Haskell, Java, Kotlin, OCaml, Python, and Rust, though usability varies by language. Build actions can run remotely through services exposing Bazel's remote execution API; the project lists BuildBarn, BuildBuddy, EngFlow, and NativeLink as compatible with its distributed compilation support. Buck2 supports filesystem watching and can integrate with Meta's optional Eden virtual filesystem. Rules are hermetic by default and missing dependencies are errors, but local-only build steps are not sandboxed. The project describes Buck2 as early-stage and says it has no stable release tag; its latest binary tag changes with repository pushes. It warns that outside users may encounter rough edges, missing features, and missing toolchains. Source and binaries are available under MIT and Apache-2.0 licenses. The project directs users to GitHub for issue reports and offers a community Discord server.