Just

Just runs named commands out of a justfile, so just build means the same thing everywhere, including CI. It is a command runner, not a build system, written in Rust and released into the public domain under CC0. The syntax borrows from Make without the tab sensitivity or implicit rules.

Single binary, no daemon, no account, nothing to host. Variables, arguments, conditionals, and per-recipe shell selection (bash, PowerShell, Python) are built in, cross-platform. Version 1.54 added a [cache] attribute that hashes declared input files and skips a recipe when nothing changed, gated behind set unstable.

Solo developers get a home for commands living in shell history. Small and medium teams get onboarding: a new hire runs just --list and sees everything the project does. Large teams run it beside the real build system, not instead of it. go-task/task is the closest alternative, YAML instead of a custom format.

The catch: the maintainers call cached recipes inherently fragile, and they mean it. The cache key captures declared inputs and little else, so system libraries and network state can shift underneath you while Just skips the recipe anyway. For dependency-driven builds, use Make. Just orchestrates commands, and at that it is excellent.