Knock vs Resend
Side-by-side trajectory, velocity, and editorial themes.
Knock keeps widening from a notifications API into an agent-driven engagement platform
Knock remains a developer-first notifications infrastructure product, but recent releases push past send-a-message plumbing. The last month added warehouse sync for delivery and engagement events, a hosted end-user preference center, dashboard MFA, and faster workflow testing. Data now moves both into Knock (Shopify) and back out to the warehouse.
Two arcs stand out: an agentic control surface — a Slack agent that creates and schedules resources, plus dashboard/CLI/agent parity for building audiences — and a maturing enterprise posture via MFA, the preference center, and warehouse analytics. Knock is positioning as a system of record for customer engagement, not just a delivery layer.
Expect the agent surface to deepen so more resources are manageable conversationally, and more data connectors after Shopify, given the warehouse-sync and dynamic-audiences direction.
Resend goes agent-native with a hosted, OAuth-backed MCP server for email.
Resend is a developer-first email API that has spent the last quarter widening on two fronts. It is building an agent-native surface — an official Claude Code plugin, mentions in AI chats, and now a hosted MCP server — while also creeping past transactional email into audience tooling with CSV contact import, in-email charts, and richer editor previews. The core remains a clean API for sending mail.
The direction is Resend-as-infrastructure that both humans and agents call directly. The MCP thread — a plugin in May, a hosted server in July — turns email into a tool an LLM can invoke over OAuth rather than hand-rolled keys, while the contacts and broadcast work points at competing with marketing-email incumbents, not just transactional senders. Distribution is shifting toward embedding where developers already are, via Vercel's marketplace and Auth0.
Expect the MCP surface to grow from sending into contact and analytics operations, and the audience and broadcast side to keep maturing toward a full marketing-email offering.
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