Buck2 vs Nx

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.

Nx is a build system for JavaScript and TypeScript monorepos, with plugins that can extend its work to other languages. It builds project and task graphs, follows task dependencies, and runs work in parallel where possible. Nx Core provides local caching; Nx Cloud adds a remote cache shared by teams and CI, and can distribute tasks across Nx Agents according to CPU and memory use. Plugins can infer tasks, generate or alter code, update dependencies, and provide executors. Documented integrations include Angular, React, Vue, Node.js, Java, .NET, Vite, Webpack, Rspack, Jest, Cypress, and Playwright. Nx also provides CI workflow setup for GitHub, CircleCI, GitLab, Azure Pipelines, Jenkins, and Bitbucket Pipelines. Nx Cloud describes trusted-branch cache writes, artifact traceability, and invalidation of artifacts made with revoked tokens. API communications are encrypted in transit, and task artifacts can be encrypted end to end before remote caching. Hobby is free forever, with monthly credits, contributor and CI-connection limits; Team is $29/month, with additional listed charges for usage, contributors, and connections.