Install Claude Code

What install claude code actually does

Installing Claude Code places a CLI binary on your PATH via the npm global package registry. There is no separate installer file to download, no GUI wizard to step through, and no system service to register. One npm command fetches the package, links the binary, and the shell can reach it immediately.

The package ships with the CLI itself, a default set of skill manifests, and the auth helper that handles the API key handshake. Every subsequent update also goes through npm update -g @anthropic-ai/claude-code, so the install mechanism doubles as the upgrade path. You do not need administrative rights on macOS or Linux if your Node.js global prefix is inside your home directory; on Windows you may need to run the terminal as Administrator depending on how Node was installed.

Prerequisites by operating system

All three platforms share the same core requirement: Node.js 18 or later. Beyond that, each OS has one or two platform-specific steps worth knowing before you start.

macOS — The default Terminal app works fine. If you manage packages with Homebrew, install Node via brew install node and skip the Node.js download entirely. Shell profiles on modern macOS default to ~/.zshrc; that is where the API key export line should live.

Windows — Two routes exist: the native PowerShell path and the WSL-based route. The native path is faster to set up; WSL avoids line-ending headaches for teams that use Linux in production. Both are covered in detail on the claude code windows page. For either route, install Node from the official installer and make sure the installer's option to add Node to PATH is checked.

Linux — Install Node via your distro's package manager (apt, dnf, or pacman) or via a version manager like nvm. The install command for Claude Code is identical regardless of distribution. If your corporate proxy intercepts HTTPS traffic, set HTTPS_PROXY before running npm.

Install command by platform

The table below shows the install command and its prerequisites for each supported operating system. The command is the same on macOS and Linux; the Windows entry shows the PowerShell variant.

OS	Prerequisite	Install command
macOS (Terminal / zsh)	Node.js ≥ 18, npm ≥ 9	npm install -g @anthropic-ai/claude-code
Windows (PowerShell)	Node.js ≥ 18 (official installer), npm ≥ 9	npm install -g @anthropic-ai/claude-code
Windows (WSL / Ubuntu)	WSL2, Node.js ≥ 18 inside WSL	npm install -g @anthropic-ai/claude-code
Linux (Debian/Ubuntu)	Node.js ≥ 18 via apt or nvm	npm install -g @anthropic-ai/claude-code
Linux (Fedora/RHEL)	Node.js ≥ 18 via dnf or nvm	npm install -g @anthropic-ai/claude-code

Running the install step by step

Follow these steps in order. Each one builds on the previous, and skipping step two is the most frequent reason people end up with a working binary that immediately fails on the first API call.

Step 1 — Check your Node version

Open a terminal and run the version check before anything else.

node --version
# expected: v18.x.x or higher

npm --version
# expected: 9.x.x or higher

If Node is below 18, upgrade now. On macOS with Homebrew: brew upgrade node. On Linux: use your package manager or switch to nvm use 20. On Windows: download the current LTS installer from the Node.js site and re-run it.

Step 2 — Run the npm install

With Node confirmed at 18 or above, run the global install.

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

The command pulls the package from the npm registry, installs it globally, and links the binary. On a typical broadband connection it takes ten to thirty seconds. If npm reports a permissions error on macOS or Linux, the fix is usually to either use nvm (which puts the global prefix inside your home directory) or to take ownership of the npm prefix directory — never run npm with sudo.

Step 3 — Verify the binary

Confirm the CLI is on your PATH.

claude --version

If the shell reports "command not found", the npm global bin directory is not in PATH. On macOS with the system Node, add export PATH="$(npm prefix -g)/bin:$PATH" to your ~/.zshrc and run source ~/.zshrc.

Step 4 — Set the API key

Add the key export to your shell profile so it persists across sessions.

# macOS / Linux: add to ~/.zshrc or ~/.bash_profile
export ANTHROPIC_API_KEY="sk-ant-..."

# Reload the profile
source ~/.zshrc

On Windows PowerShell, add the variable to your profile script ($PROFILE) or set it as a system environment variable via the Control Panel. The CLI setup page covers the full list of optional variables.

Step 5 — Run the auth check

Confirm the key is accepted before opening a project.

claude auth

A successful auth check prints a confirmation line with the account email. If it fails with a 401, the key is either malformed or the export line was not reloaded. If it fails with a network error, check HTTPS_PROXY settings first.

Chinese-language documentation

For Chinese-language install and usage tutorials (claude code 安装), the claude code tutorials page includes a dedicated section with step-by-step content in Simplified Chinese.

Keeping Claude Code up to date

Claude Code releases follow the npm versioning cadence. To update to the latest version, run the same install command with the latest tag or use the update shorthand.

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

# Or pin to a specific version
npm install -g @anthropic-ai/claude-code@1.5.0

Check the currently installed version at any time with claude --version. The Claude Code download page lists the current stable release and the version naming convention used across packages.

For context on the safety framing around AI developer tools, the NIST AI Risk Management Framework is a useful reference when evaluating deployment policies for your team.