claude-code-best-practice/tutorial/day0/windows.md

Windows Setup

Back to Day 0

Prerequisites

You need Node.js v18 or higher and npm (bundled with Node.js).

Step 1: Install Node.js

Option A: Via nodejs.org Download Page with fnm (Recommended)

fnm (Fast Node Manager) is officially recommended by Node.js. It's fast, lightweight, and lets you switch Node versions easily if needed later.

1. Open your browser and go to nodejs.org/en/download.

2. You'll see a row of dropdowns that says: "Get Node.js® vXX.XX.X (LTS) for __ using __ with __". Set the dropdowns as follows:

   Dropdown	Select
   Version	vXX.XX.X (LTS) — keep the default LTS version, don't change it
   OS	Windows
   Package Manager	fnm (under "Recommended (Official)")
   Package Format	npm — keep the default

3. The page will show you the exact commands to run. Open PowerShell as Administrator (right-click the Start menu > "Terminal (Admin)" or search for PowerShell > right-click > "Run as administrator").

4. Copy and paste the commands from the page. They will look something like this:

   # Step 1 — Install fnm
   winget install Schniz.fnm
   
   # Step 2 — Configure fnm environment (add to your PowerShell profile)
   fnm env --use-on-cd --shell powershell | Out-String | Invoke-Expression
   
   # Step 3 — Install Node.js
   fnm install 24   # The page will show the exact version number
   

   The version number may differ from above — always use whatever the website shows.

5. Close and reopen your terminal after installation. This is important so that node and npm are available in your PATH.

Why fnm? It's in the "Recommended (Official)" category on the Node.js download page, installs in seconds (written in Rust), and works natively on Windows — unlike nvm which requires a separate community port for Windows.

Option B: Official .msi Installer (Alternative)

If you prefer a traditional installer:

1. Go to nodejs.org. The homepage shows a big "Download Node.js (LTS)" button.
2. Click it to download the .msi file.
3. Run the installer:
   • Click Next through the wizard.
   • Accept the license agreement.
   • Keep the default install location (C:\Program Files\nodejs\).
   • On the "Tools for Native Modules" screen, check the box for "Automatically install the necessary tools" — this installs build tools you may need later.
   • Click Install and wait for it to finish.
4. Restart your terminal after installation.

Option C: Using winget (One-liner)

If you have winget (built into Windows 10/11):

winget install OpenJS.NodeJS.LTS

Close and reopen your terminal after installation.

Step 2: Verify Node.js

Open a new terminal (Command Prompt, PowerShell, or Windows Terminal) and run:

node --version
npm --version

Both commands should print version numbers. If you get "not recognized", restart your terminal or check that Node.js is in your PATH.

Step 3: Install Claude Code

npm install -g @anthropic-ai/claude-code

If you get a permission error, open your terminal as Administrator (right-click > Run as administrator) and run the command again.

Step 4: Verify Claude Code

claude --version

You should see the Claude Code version printed. Now head back to Day0.md for authentication setup.

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Notes

• Recommended terminal: Windows Terminal or PowerShell. The classic Command Prompt works but has limited features.
• WSL users: If you prefer running Claude Code inside WSL (Windows Subsystem for Linux), follow the Linux guide instead — WSL is a full Linux environment.
• PATH issues: If claude is not recognized after install, npm's global bin directory may not be in your PATH. Run npm config get prefix to find it, then add the resulting path to your system's PATH environment variable.