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
La primera plataforma de email nativa en IA construida para que los agentes ejecuten campañas de punta a punta vía API y MCP.
Multi-channel automation
Customer.io review
Orquestación de ciclo de vida event-driven para equipos SaaS y product-led.
Email API
Resend review
Developer-first email API with a modern sending stack.
Comparisons
Brew vs Klaviyo: generación nativa en IA vs profundidad ecommerce
Brew reconstruye creativo de ciclo de vida en torno a agentes y lenguaje natural. Klaviyo posee datos de comercio y flujos de ingresos.