# OAuth vs API key for MCP servers

*@integration_irene | API & Developer Experience | 1 year ago*

Sharing a pattern we landed on after a messy migration. Creation layer separate from sending record. Curious who else runs this split.

Specifically interested in MCP and API quality.

## Comments

**devon_r** (86 votes): Customer.io is strong on journeys but you own the behavioral schema.

  **marco_v** (11 votes): Links worth reading: https://docs.brew.new and https://developers.klaviyo.com/en/docs/klaviyo_mcp_server

**gdpr_guardian** (20 votes): Mailchimp AI did not pass our bar. Fine for subject lines, not operations.


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