Claude Code

This guide will walk you through installing Claude Code, Anthropic's powerful command-line AI assistant, and configuring it to work with the WhoisXML API MCP Server. Claude Code brings AI directly to your terminal, allowing you to build features, debug issues, and automate tasks from the command line.

System Requirements

Before installing Claude Code, ensure your system meets these requirements:

Operating Systems: macOS 10.15+, Ubuntu 20.04+/Debian 10+, or Windows 10+ (with WSL)
Hardware: Minimum 4GB RAM (16GB recommended)
Software: Node.js 22+ LTS (required)
Network: Active internet connection for authentication and AI processing
Shell: Works best in Bash, Zsh, or Fish
Storage: At least 500MB available disk space

Installing Node.js

Claude Code requires Node.js version 22+ LTS or higher to use npx for running the WhoisXML API MCP Server.

📋 Complete Node.js Installation Guide →

The standalone Node.js guide covers installation for all platforms (macOS, Windows, Linux) with multiple methods and troubleshooting tips.

Quick Verification

If you already have Node.js installed, verify it meets the requirements:

# Check Node.js version (should be 22.x LTS or higher)
node --version

# Check npm version
npm --version

# Test Node.js
node -e "console.log('Node.js is working!')"

If you don't have Node.js or need to upgrade, follow the Node.js Installation Guide before continuing.

Installing Claude Code

Once Node.js is installed, you can install Claude Code globally using npm.

Step 1: Install Claude Code

# Install Claude Code globally
npm install -g @anthropic-ai/claude-code

# Verify installation
claude --version

Avoid Using sudo

Do not use sudo with npm to prevent permission issues. If you encounter permission errors, configure npm properly or use a Node version manager like nvm.

Step 2: Initial Setup and Authentication

Navigate to your project directory:
```
cd /path/to/your/project
```
Start Claude Code for the first time:
```
claude
```
Authenticate with Anthropic:
- Follow the on-screen prompts to authenticate
- You'll need either:
  - An Anthropic Console account with API credits
  - A Claude.ai subscription

Complete the setup:

# Configure Claude Code settings
claude config

Setting Up WhoisXML API MCP Server

Now let's configure Claude Code to work with the WhoisXML API MCP Server for enhanced domain intelligence capabilities.

Prerequisites

Before setting up the MCP server, ensure you have:

A valid WhoisXMLAPI account and API token
Claude Code successfully installed and authenticated

Step 1: Add the WhoisXML API MCP Server

Claude Code provides several options for adding MCP servers. The recommended approach is using npx, which runs the server directly without requiring package installation or dependency management.

Option 1: Using npx (Recommended)

# Add WhoisXML API MCP Server using npx
claude mcp add whoisxmlapi \
  --env WHOISXMLAPI_TOKEN=your-api-token-here \
  -- npx -y @whoisxmlapidotcom/mcp-whoisxmlapi

Option 2: Using Docker

# Add WhoisXML API MCP Server using Docker
claude mcp add whoisxmlapi \
  --env WHOISXMLAPI_TOKEN=your-api-token-here \
  -- docker run --rm -i \
     --env WHOISXMLAPI_TOKEN \
     whoisxmlapidotcom/mcp-whoisxmlapi:v1

Option 3: Using Binary

# Download and use the binary directly
claude mcp add whoisxmlapi \
  --env WHOISXMLAPI_TOKEN=your-api-token-here \
  -- /path/to/mcp-whoisxmlapi

Replace API Token

Make sure to replace your-api-token-here with your actual WhoisXMLAPI token. You can find your token in your WhoisXMLAPI dashboard.

Step 2: Verify MCP Server Setup

List configured servers:
```
claude mcp list
```
Check server details:
This will show the token in plain text
This will show the token in plain text. Make sure you're in a trusted environment before executing this command, as anyone viewing your screen will be able to see the WhoisXMLAPI token configured.
```
claude mcp get whoisxmlapi
```

Test the connection:

# Start Claude Code and test
claude

# In the Claude Code session, try:
# "Can you look up the WHOIS information for example.com?"

Check MCP status within Claude Code:

# Within Claude Code, use the /mcp command
/mcp

Using Claude Code with WhoisXMLAPI

Now that everything is set up, you can use Claude Code with WhoisXMLAPI tools:

Basic Commands

# Start Claude Code in your project
cd your-project
claude

# Example queries you can ask:
# - "Look up the WHOIS information for google.com"
# - "Get the DNS history for example.com"
# - "Find the IP geolocation for 8.8.8.8"
# - "Check the SSL certificates for github.com"
# - "Perform a reverse DNS lookup on 1.1.1.1"

Managing MCP Servers

Common MCP Commands

# List all configured servers
claude mcp list

# Get details for a specific server
claude mcp get whoisxmlapi

# Remove a server
claude mcp remove whoisxmlapi

# Reset project choices (if using project scope)
claude mcp reset-project-choices

Environment Variables

You can also set environment variables globally:

# Set environment variable for your session
export WHOISXMLAPI_TOKEN="your-api-token-here"

# Add to your shell profile for persistence
echo 'export WHOISXMLAPI_TOKEN="your-api-token-here"' >> ~/.bashrc
source ~/.bashrc

Troubleshooting

Common Issues

1. "Command not found: claude"

# Check if Claude Code is installed globally
npm list -g @anthropic-ai/claude-code

# Reinstall if necessary
npm uninstall -g @anthropic-ai/claude-code
npm install -g @anthropic-ai/claude-code

2. "Connection closed" errors (Windows)

# Use cmd /c wrapper on native Windows
claude mcp add whoisxmlapi -- cmd /c npx -y @whoisxmlapidotcom/mcp-whoisxmlapi

3. Authentication issues

# Re-authenticate with Claude
claude config

# Or clear configuration and start fresh
rm -rf ~/.claude
claude config

4. MCP server not starting

# Check MCP server logs
claude mcp get whoisxmlapi

# Test server manually with npx
npx -y @whoisxmlapidotcom/mcp-whoisxmlapi

# Check environment variables
echo $WHOISXMLAPI_TOKEN

Performance Tips

Use npx for simplicity: npx automatically handles updates and ensures you always run the latest version
Set timeouts: Configure MCP_TIMEOUT for slower connections:
```
MCP_TIMEOUT=10000 claude
```
Monitor usage: Keep track of your WhoisXMLAPI quota to avoid rate limits
Use Docker for consistency: Docker provides the most reliable experience if you prefer containerized deployments

Security Considerations

API Token Security

Never commit API tokens to version control
Use environment variables or secure credential storage
Regularly rotate your API tokens
Monitor API usage for unexpected activity

Next Steps

Now that Claude Code is set up with WhoisXML API MCP Server:

Explore the available tools to understand all capabilities
Check the usage guide for workflow examples
Learn about advanced configuration options
Review troubleshooting for common issues

Getting Help

If you need assistance: