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.

canvasPromptEmail AEmail BEmail CChat + edit
Whiteboard sketch showing model, agent, and harness layers for an email workflowPromptEmail AEmail BEmail CChat + edit

Agent architecture

Startup GTM email playbooks

Welcome, trial, and first-revenue sequences a seed team can ship this week.

Brew coveragePromptEmail AEmail BEmail CChat + edit

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。

Customer.io coveragePromptEmail AEmail BEmail CChat + edit

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。

Resend coveragePromptEmail AEmail BEmail CChat + edit

Email API

Resend review

Developer-first email API with a modern sending stack.

Side by side comparison of Brew and Klaviyo for AI email marketingPromptEmail AEmail BEmail CChat + edit

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。