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What is proto?

3 min

proto is a pluggable version manager, a unified toolchain.

If you're unfamiliar with the concept of a toolchain, a toolchain is a collection of tools that are downloaded, installed, and managed by version through a single interface. In the context of proto's toolchain, a tool is either a programming language, a dependency/package manager for a language, or a custom implementation provided by a plugin. It's the next step in the version manager evolution.


  • Lightspeed! With Rust and WASM, we can guarantee exceptional performance.
  • Multi-language. A single CLI for managing versions for all of your languages.
  • Cross-platform, for a consistent experience across machines and teams.
  • Contextual version detection, ensuring the correct version of a tool is always used.
  • Checksum verification, ensuring a tool came from a trusted source.
  • Detects and infers from a language's ecosystem for maximum compatibility.
  • Pluggable architecture, allowing for custom tooling.

Why proto?

proto was designed to be a modern and holistic version manager for all of your favorite programming languages. We believe a single tool that works the same across every language is better than multiple ad-hoc tools. While we only support a handful of languages today, we aim to support many more in the future!


proto powers moon's toolchain, enabling a single source of truth for both tools!

How does it work?

The toolchain is a .proto directory within the current user's home directory, e.g., ~/.proto.

The first step in a tool's life-cycle is being downloaded to ~/.proto/temp. Downloads are typically an archive that can be unpacked into a target directory. Once downloaded, we verify the downloaded file by running a checksum. If this check fails for any reason, the tool is unusable, and the process is aborted.

After a successful verification, the last step in the tool's life-cycle can begin, installation. Depending on the type of download, the installation process may differ. For archives, we unpack the tool to ~/.proto/tools/<name>/<version>. In the future, we'll support building from source.

From here, we make these tools globally available by prepending ~/.proto/shims and ~/.proto/bin to PATH (typically as part of your shell profile). Continue reading for more about these folders.

Supported tools

The following tools are officially supported in proto via moonrepo. Additional tools can be supported through third-party plugins.

Supported targets

Because proto is written in Rust, we only support targets that are explicitly compiled for, which are currently:

Operating systemArchitectureTarget
macOS 64-bitIntelx86_64-apple-darwin
macOS 64-bitARMaarch64-apple-darwin
Linux 64-bitIntel GNUx86_64-unknown-linux-gnu
Linux 64-bitIntel muslx86_64-unknown-linux-musl
Linux 64-bitARM GNUaarch64-unknown-linux-gnu
Linux 64-bitARM muslaarch64-unknown-linux-musl
Windows 64-bitIntelx86_64-pc-windows-msvc