🔑 Your Mailchimp API key connects Mailchimp MCP to your Mailchimp account. This guide shows you exactly how to get it.

What You'll Learn

• How to find your API key in Mailchimp
• How to create a new API key
• How to understand the key format
• Security best practices

Time: 2 minutes
Difficulty: Easy

Step-by-Step Instructions

Step 1: Log Into Mailchimp

1. Go to mailchimp.com
2. Log into your account
3. Make sure you're on the account you want to connect

Step 2: Navigate to API Keys

1. Click your profile icon (top right corner)
2. Select Account & Billing
3. Click the Extras tab
4. Click API keys

Step 3: Create a New API Key

1. Click Create A Key button
2. Mailchimp will generate a new API key
3. The key will look like: abc123def456-us9

Step 4: Copy Your API Key

1. Click the eye icon to reveal the key
2. Click Copy to copy the entire key
3. Important: Copy the entire key including the server prefix (e.g., -us9)

Warning: You can only see the full key once. Copy it immediately and store it securely.

Understanding Your API Key

Key Format

Your API key has two parts:

• API Key: abc123def456 (the main key)
• Server Prefix: us9 (your Mailchimp data center)

Full format: abc123def456-us9

Server Prefix Explained

The server prefix indicates your Mailchimp data center:

• us1, us2, us3, etc. - United States
• eu1, eu2, etc. - Europe
• Other regional prefixes

Note: Mailchimp MCP automatically detects the server prefix from your API key—you don't need to configure it separately.

Storing Your Key Securely

Do This

• Store in .env file (not committed to git)
• Use environment variables
• Keep in a password manager
• Enable disk encryption on your computer

Don't Do This

• Share your key publicly
• Commit to version control
• Email or message the key
• Store in plain text files

API Key Permissions

Read-Only Keys (AI Analyst - Free)

For the free tier, you can use read-only API keys:

• View audiences and campaigns
• Access reports and analytics
• Read member information
• Cannot create or modify content

Full Access Keys (AI Marketer + Account Manager - Paid)

For the paid tier:

• All read permissions
• Create and send campaigns
• Manage members and segments
• Create automation workflows

Security Best Practices

Use Read-Only Keys When Possible

For testing and exploration, use read-only keys to limit access if compromised.

Rotate Keys Regularly

Change your API keys every 90 days or:

• After team members leave
• If you suspect compromise
• When switching accounts

Never Share Keys

Never share your API key with unauthorized users. Each person should have their own key if needed.

Revoke Compromised Keys Immediately

If your key is exposed:

1. Immediately revoke it in Mailchimp
2. Create a new API key
3. Update your configuration
4. Review access logs

Troubleshooting

Key Not Working

Check these:

• Key format is correct (abc123-us9)
• Key hasn't been revoked
• Server prefix matches your account
• Key has necessary permissions

Permission Errors

If you see permission errors:

• Verify key has required permissions
• Check if key is read-only when write access needed
• Create new key with appropriate permissions

Key Format Issues

Common mistakes:

• Missing server prefix (-us9)
• Extra spaces or characters
• Copy/paste errors

Solution: Copy the entire key including the server prefix.

Using Your API Key

In Mailchimp MCP Setup

1. Run mailchimp-mcp-config or use the setup UI
2. Paste your API key when prompted
3. The server prefix is automatically detected
4. Save configuration
5. Restart Claude Desktop

Environment Variables

Add to your .env file:

MAILCHIMP_API_KEY=your-api-key-here
MAILCHIMP_SERVER_PREFIX=us9

Note: The server prefix is optional since it's automatically detected from your API key.

Next Steps

After getting your API key:

1. Install Mailchimp MCP
2. Configure with your API key
3. Test the connection
4. Start using Claude with Mailchimp!

Need Help?

• Troubleshooting Guide
• API Key Best Practices
• Contact Support

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• Installation Guide
• API Key Best Practices
• Your First 5 Minutes