Buck2 vs GN
Buck2
buck2.build
GN
gn.googlesource.comSide by side
| Figure | Buck2 | GN |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 1 | 1 |
| Spec score · Build Automation Software | 8.1 (#12) | 7.9 (#15) |
| 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. | GN generates Ninja files for C, C++, Rust, Objective C, and Swift; other languages can use script-based action rules. |
| Purpose | Buck2 is a large-scale, fast, hermetic, multi-language build system and the successor to Buck. | GN is a meta-build system that generates build files for Ninja. |
| Support | The project directs users to report issues through GitHub and provides a community Discord server. | Users can report bugs in the GN bug database and ask questions or follow development on the Chromium GN developers Google Group. |
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.