Sign-up confirmations, password resets, receipts, the alert you send yourself: every app sends email, and doing it from your own SMTP server means fighting spam filters forever. Resend is a send API built for developers — a few lines to send, React components for templates, and delivery logs you can actually read.

Free tier

3,000 emails per month, capped at 100 per day, plus 1,000 marketing contacts. Not a trial. The daily cap is the one to design around: a batch that mails every user at once will hit it long before the monthly number.

Send your first email 

  npm install resend
  
  import { Resend } from "resend";

const resend = new Resend(process.env.RESEND_API_KEY);

await resend.emails.send({
  from: "onboarding@resend.dev",       // testing only — see below
  to: "you@example.com",
  subject: "It works",
  html: "<p>Hello from the app.</p>",
});

onboarding@resend.dev sends without any setup, but only to the address you signed up with. It’s for proving the wiring, nothing more.

Verify a domain, or nothing lands

To send as hello@yourdomain.com, add the domain in the dashboard and copy the records it gives you into your DNS:

RecordWhat it does
MX + TXT on a subdomainSPF — says Resend may send for you
TXT (DKIM)Signs the message so it can’t be forged
TXT (DMARC)Tells receivers what to do with mail that fails the first two

Verification takes minutes to a few hours. Skipping DMARC is the usual reason mail reaches Gmail’s spam folder while your own tests looked fine.

Send from a subdomain — mail.yourdomain.com — so that a reputation problem with automated mail never touches your personal address on the apex domain.

Templates as components

If you’re already in React, write the email as one:

  npm install @react-email/components
  
  export function Welcome({ name }) {
  return (
    <Html>
      <Text>Hi {name}, thanks for signing up.</Text>
      <Button href="https://example.com/start">Get started</Button>
    </Html>
  );
}
  
  await resend.emails.send({
  from: "hello@mail.yourdomain.com",
  to: user.email,
  subject: "Welcome",
  react: <Welcome name={user.name} />,
});

Email HTML is a decade behind the web — tables, inline styles, no flexbox worth relying on. Letting the library render it is the point.

Webhooks for what happened next

Point a webhook at your app and Resend posts email.delivered, email.bounced, and email.complained events. Store bounces and stop sending to those addresses: a list full of dead addresses is how a sending domain loses its reputation.

Habits worth keeping

  • Never send from a request handler. A slow provider becomes a slow sign-up. Queue it, or send it after you’ve responded.
  • Make sends idempotent. A retried webhook that re-sends a receipt is a support ticket.
  • Keep a RESEND_API_KEY per environment so a staging test can’t mail real users.
  • Log the returned id. It’s how you find one message among thousands in the dashboard when a customer says nothing arrived.

Next

Work that shouldn’t happen inside a request → Inngest

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Last updated 23 Aug 2026, 00:00 UTC. history