Cargo vs Spago

Cargo is the free package manager and build tool for Rust, used through a command-line interface. It downloads dependencies, builds packages, and supports repeatable builds with lockfiles. Developers can compile, check, document, test, run, package, install, and publish Rust projects. The `cargo new` command creates a package, defaulting to a binary; adding `--lib` creates a library. Cargo uses crates.io by default and also handles alternate registries, Git dependencies, and local paths. Workspaces allow multiple packages to share a lockfile and output directory. Package features can enable conditional compilation and optional dependencies. In offline mode, Cargo avoids network access and attempts to use cached data. It supports authentication options for registries and new subcommands without modifying Cargo itself. Rustup installs Cargo with the stable Rust release, and installation instructions cover Windows, macOS, Linux, and other Unix-like systems. Cargo is open source under the MIT and Apache License, Version 2.0. Some documented capabilities remain unstable and require a nightly toolchain and `-Z` flags.

Spago has no write-up on Specifiction yet; its figures are above.