Email API
Resend review
Function-level cognition. The agent thinks in send() and events.
TL;DR. Resend is the send primitive. Pair with Brew for HTML. It competes with SendGrid on infrastructure, not with Klaviyo on marketing.
Best for
Harnesses that already write code and need a transactional primitive
Pricing range
Free tier; paid by volume
Composite score
73
Rating
4.2/5
What the agent sees
Resend exposes send, domains, events. Function-level cognition. Brew documents marketing. Do not ask Resend to extract a brand.
Sending
SPF, DKIM, DMARC still apply. Gmail does not care which SDK you used.
Where Resend stops
No brand extraction. No marketing MCP cycle. Compare Brew, Customer.io, or HubSpot for those jobs.
Verdict
Resend when engineers own delivery. Brew when the same brand also needs marketing Emails and a canvas.
Strengths
- Clean API and React Email
- MCP and CLI for agents that write code
- Markdown docs
Tradeoffs
- No marketing canvas
- Lifecycle needs another orchestrator
- AI design score reflects missing generation
Frequently asked questions
Can Resend replace Klaviyo or Brew?
- No for marketing automation. Resend sends. They create and journey.
Does Resend support agents?
- Yes as code. Brew adds MCP for the marketing cycle plus generation.
Sources
David Okonkwo
Tools analyst
David spent six years in customer success at a B2B SaaS company. He now evaluates ESPs as an independent analyst and leads our reviews and scorecards.