🛡️ Mailchimp MCP is designed with privacy and security as foundational principles. Learn how your data is protected and what you need to know about security best practices.

What You'll Learn

• How local-first architecture protects your data
• Privacy controls and PII masking
• Security best practices
• How to protect sensitive information

Time: 10 minutes
Difficulty: Intermediate

Local-First Architecture

All data processing happens on your machine—no cloud storage.

The Mailchimp MCP server runs entirely on your local computer. This means:

• No cloud storage of your Mailchimp data
• Local processing before data reaches Claude Desktop
• Full control over what data is exposed
• Optional PII masking for sensitive information

How It Works

1. MCP Server runs locally on your machine
2. Claude Desktop communicates with the MCP server via local stdio
3. Data flows from Mailchimp API → MCP Server (local) → Claude Desktop → Claude AI
4. Masking happens locally before data reaches Claude Desktop (if enabled)

Privacy Controls

PII Masking

PII (Personally Identifiable Information) masking automatically obscures sensitive data before it leaves your machine. When enabled:

• Email addresses: john.doe@example.com → j***@example.com
• Names: John Doe → J***
• Phone numbers: +1-555-123-4567 → ***-***-4567
• IP addresses: 192.168.1.1 → 192.***.***.***
• Location data: Rounded to city-level precision

Enable PII masking by setting MAILCHIMP_MASK_PII=true in your environment variables.

Conversation History

Claude Desktop stores conversation history locally on your computer:

• macOS: ~/Library/Application Support/Claude/
• Windows: %APPDATA%\Claude\
• Linux: ~/.config/Claude/

Best Practice: Regularly review and delete conversation history, especially when working with sensitive client data.

Security Best Practices

Use Read-Only API Keys When Possible

For testing and exploration, use read-only API keys. This limits what can be accessed even if the key is compromised.

Enable PII Masking for Sensitive Accounts

If you're working with sensitive customer data (especially for account managers managing client accounts), enable PII masking:

export MAILCHIMP_MASK_PII=true

Review Conversation History Regularly

Claude Desktop stores all conversations locally. Regularly review and delete history containing sensitive information.

Use Disk Encryption

Enable full disk encryption on your computer to protect data at rest.

Rotate API Keys Periodically

Change your Mailchimp API keys periodically, especially if you suspect any compromise.

Restart After Changing API Keys

Always restart Claude Desktop completely after changing API keys to clear cached resources.

Security Risks & Mitigations

PII Exposure Risk

Risk: Personal information may be exposed in Claude Desktop conversations.

Mitigation:

• Enable PII masking for sensitive accounts
• Only query necessary fields
• Avoid bulk member queries when possible
• Review conversation history regularly

API Key Compromise

Risk: API keys may be exposed or compromised.

Mitigation:

• Use read-only keys when possible
• Store keys securely (.env file, encrypted disk)
• Rotate keys periodically
• Never commit keys to version control
• Revoke compromised keys immediately

Conversation History Exposure

Risk: Conversation history stored locally may be accessed.

Mitigation:

• Enable disk encryption
• Regularly delete sensitive conversations
• Use PII masking for sensitive queries
• Secure your computer physically

Compliance Considerations

GDPR

PII masking helps protect subscriber personal data and supports GDPR compliance. However, PII masking is a tool, not a complete compliance solution. Consult compliance experts for specific regulatory requirements.

HIPAA

For healthcare data, ensure you have appropriate Business Associate Agreements (BAAs) in place and follow HIPAA guidelines for data handling.

Other Regulations

Consult with compliance experts for specific regulatory requirements in your industry or jurisdiction.

Data Flow & Storage

Where Data Is Stored

• Mailchimp: Your Mailchimp account data (as usual)
• Local MCP Server: Temporary processing (no persistent storage)
• Claude Desktop: Conversation history (local only)
• Claude AI: Conversation data (subject to Claude's privacy policy)

What Data Is Shared

• Only data you explicitly query is sent to Claude AI
• PII masking can obscure sensitive fields before transmission
• No data is stored in cloud services by Mailchimp MCP

Best Practices Summary

1. Use read-only API keys when possible
2. Enable PII masking for sensitive accounts
3. Review conversation history regularly
4. Use disk encryption
5. Rotate API keys periodically
6. Restart after changing API keys
7. Secure your computer physically
8. Follow your organization's security policies

Need Help?

• PII Masking Guide
• API Key Best Practices
• Getting Help and Support

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Related Articles:

• PII Masking Guide
• API Key Best Practices
• Getting Help and Support