How to Install and Use fnm: The Fast Rust‑Based Node.js Version Manager

Overview

fnm is a Node.js version manager written in Rust. It works on macOS, Linux and Windows and manages Node versions by downloading official binaries.

Installation

Unix‑like (WSL, macOS, Linux)

# Initial install
curl -fsSL https://fnm.vercel.app/install | bash

# Upgrade later (skip modifying the current shell)
curl -fsSL https://fnm.vercel.app/install | bash -s -- --skip-shell

# Enable automatic version switching and optional mirror
# Add the following line to your shell profile (e.g., ~/.zshrc or ~/.bashrc)
eval "$(fnm env --use-on-cd --node-dist-mirror=https://repo.huaweicloud.com/nodejs/)"

Windows

Download fnm.exe from the official release page, place it in a directory (e.g., D:\fnm) and add that directory to the system PATH. Then run the following in PowerShell to enable automatic switching:

fnm env --use-on-cd | Out-String | Invoke-Expression

Managing Node versions

Installation commands

# Install the latest LTS release
fnm install --lts

# Install the newest version of a major release (e.g., 18.x)
fnm install 18

# Install an exact version
fnm install 18.21.1

To remove a version or its alias:

fnm uninstall 18.21.1          # remove a specific version
fnm uninstall v18             # remove an alias (also deletes the alias)

Selecting a version for the current shell

# Use the system‑installed Node
fnm use system

# Use a specific installed version
fnm use 18.21.1

# Use the latest installed version of a major release
fnm use 18

After fnm use <version> the chosen version becomes the default for all new shell sessions.

Aliases

# Create an alias for a version
fnm alias 18.21.1 v18

# Switch using the alias
fnm use v18

Common commands

# Show help
fnm --help

# List installed versions
fnm list

# Set a default version that will be used when no other version is selected
fnm default 18.21.1