# mason.nvim — Portable Package Manager for Neovim LSP, DAP & Linters

> A Neovim plugin that installs and manages LSP servers, DAP adapters, linters, and formatters from a unified registry, with a built-in UI and automatic PATH management.

## Install

Save in your project root:

# mason.nvim — Portable Package Manager for Neovim LSP, DAP & Linters

## Quick Use
```lua
-- In your lazy.nvim config:
{ "williamboman/mason.nvim", config = true }
-- Then in Neovim, run:
-- :Mason to open the package manager UI
-- :MasonInstall lua-language-server stylua to install packages
```

## Introduction
mason.nvim is a Neovim plugin that provides a portable package manager for external editor tooling. It handles downloading, installing, and updating LSP servers, DAP debug adapters, linters, and formatters into a self-contained directory, keeping your system clean and your Neovim environment reproducible.

## What mason.nvim Does
- Installs LSP servers, DAP adapters, linters, and formatters from a curated registry
- Provides a floating window UI for browsing, installing, and updating packages
- Manages a dedicated installation directory separate from system paths
- Automatically configures PATH so Neovim can find installed tools
- Supports companion plugins for automatic integration with nvim-lspconfig and null-ls

## Architecture Overview
mason.nvim maintains a registry of package definitions that describe how to download and install each tool. Packages are installed into a data directory (typically ~/.local/share/nvim/mason) using platform-appropriate methods: npm, pip, cargo, go install, or direct binary downloads. The plugin prepends its bin directory to Neovim's PATH, making installed tools available to LSP clients, formatters, and linters without global installation.

## Self-Hosting & Configuration
- Requires Neovim 0.7+ and Git; some packages need Node.js, Python, or other runtimes
- Install via lazy.nvim, packer.nvim, or any Neovim plugin manager
- Pair with mason-lspconfig.nvim for automatic LSP server setup with nvim-lspconfig
- Configure default package lists with ensure_installed in the setup function
- Custom registries can override or extend the default package definitions

## Key Features
- Unified interface for tools that would otherwise require separate install steps
- Cross-platform support for macOS, Linux, and Windows without manual binary management
- Version pinning ensures reproducible setups across machines
- Health check command (:checkhealth mason) diagnoses missing dependencies
- Extensible registry format lets users add private or internal tool packages

## Comparison with Similar Tools
- **nvim-lsp-installer** — predecessor to mason.nvim (now deprecated); LSP-only scope
- **null-ls / none-ls** — injects non-LSP sources into the LSP client; mason installs the tools these use
- **Homebrew** — system-wide package manager; mason keeps tools scoped to Neovim
- **mise / asdf** — version managers for runtimes; mason focuses specifically on editor tooling
- **COC.nvim** — VS Code extension host for Neovim; manages extensions differently than standalone tools

## FAQ
**Q: Does mason.nvim replace nvim-lspconfig?**
A: No. mason.nvim installs LSP servers; nvim-lspconfig configures them. Use mason-lspconfig.nvim to bridge the two.

**Q: Where are packages installed?**
A: By default in ~/.local/share/nvim/mason. Override this with the install_root_dir option in the setup call.

**Q: Can I use mason.nvim without lazy.nvim?**
A: Yes. mason.nvim works with any Neovim plugin manager including packer.nvim, vim-plug, and manual installation.

**Q: How do I update all installed packages?**
A: Open the Mason UI with :Mason and press U to update all, or run :MasonUpdate from the command line.

## Sources
- https://github.com/williamboman/mason.nvim
- https://mason-registry.dev

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Source: https://tokrepo.com/en/workflows/asset-a1e83bbf
Author: AI Open Source