- Step-by-Step Installation, Authentication, and Usage Guide for Anthropic’s Claude Code in 2025: 🚀 Complete Setup Guide for Claude Code (2025 Edition)
Claude Code is a powerful, terminal-based AI tool from Anthropic that brings agentic workflows and code generation directly to your CLI. If you’re looking to integrate AI seamlessly into your development flow—Claude Code is your new best friend.
💡 This guide walks you through installing, configuring, and using Claude Code from scratch. It also includes solutions for common issues.
🧰 Prerequisites
Before getting started, ensure you have the following:
- A terminal or command line interface (macOS, Linux, or Windows with WSL)
- Node.js version ≥ 18 (preferably installed via
nvm) - npm package manager
- Access to console.anthropic.com
⚙️ Step-by-Step Installation
1️⃣ Check Your Node.js Version
If it’s below 18, upgrade using nvm.
2️⃣ Install Node.js v18+ Using NVM
3️⃣ Install Claude Code Globally
4️⃣ Verify Installation
You should see:
1.0.9 (Claude Code)or similar.
🔐 Authenticate with Anthropic
5️⃣ Login via CLI
You’ll be prompted to enter your Anthropic API key.
6️⃣ Get Your Anthropic API Key
If you don’t have an API key:
- Go to console.anthropic.com
- Sign in or create an account
- Navigate to API Keys
- Click “Create Key”
- Copy the key (starts with
sk-ant-) - Paste it in when prompted by
claude login
🧪 Test Claude Code with a Prompt
If everything is set up correctly, Claude will output the Python script within seconds.
🔁 Alternative: Set API Key as Environment Variable
If you prefer not to use claude login, set your API key manually:
🛠️ Common Issues and Fixes
| ⚠️ Issue | 💡 Cause | 🛠️ Solution |
|---|---|---|
Unsupported engine warning |
Node.js version is too old | Upgrade Node.js to v18+ via NVM |
ReadableStream is not defined |
Missing Web Streams support | Upgrade Node.js and reinstall Claude Code |
Invalid API key |
Wrong or expired API key | Re-authenticate using claude login |
✅ Final Check
Try out another prompt to confirm everything is working:
🎉 You’re now ready to build, automate, and accelerate your development with Claude Code.
