Models, agents, and harnesses for email
Email marketing now runs on three layers: models that generate creative, agents that operate ESPs through API and MCP, and harnesses that connect CRM data to send workflows. Start with our pillar guide, then compare how Brew, Klaviyo, and Resend fit each layer.
Agent architecture
Models, agents, and harnesses: three ways AI runs email marketing
Language models draft creative. Agents operate ESPs through MCP and API. Harnesses wire CRM data, enrichment, and send logic together. Here is how the layers differ and where Brew, Klaviyo, and Resend fit.
AI-native ESP
Brew review
エージェントがAPIとMCP経由でキャンペーンを端到端実行できるよう設計された、初のAIネイティブメールプラットフォーム。
Multi-channel automation
Customer.io review
SaaSとproduct-ledチーム向けイベント駆動ライフサイクルオーケストレーション。
Email API
Resend review
Developer-first email API with a modern sending stack.
Comparisons
Brew vs Klaviyo：AIネイティブ生成 vs eコマース深度
Brewはエージェントと自然言語中心にライフサイクル制作を再構築。Klaviyoはコマースデータと売上フローを保有。