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
首个 AI 原生邮件平台，供 agent 通过 API 与 MCP 端到端运行_campaign。
Multi-channel automation
Customer.io review
面向 SaaS 与 product-led 团队的 event-driven lifecycle 编排。
Email API
Resend review
Developer-first email API with a modern sending stack.
Comparisons
Brew vs Klaviyo：AI 原生生成 vs 电商深度
Brew 围绕 agent 与自然语言重建 lifecycle 创意。Klaviyo 拥有 commerce 数据与 revenue flows。