Resend

Email API built for developers — send transactional email from your app with a minimal SDK and React Email templates.

Overview

Resend is a developer-focused email API. It has a clean SDK, supports React Email for building templates, and offers a generous free tier (3,000 emails/month).

Environment Variable

Add your API key to .env.local:

RESEND_API_KEY=re_...

Get your key from resend.com/api-keys.

Scaffolded File

src/
  lib/
    email.ts    # Resend client + sendEmail helper

`src/lib/email.ts`

import { Resend } from 'resend'

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

export async function sendEmail({
  to,
  subject,
  html,
}: {
  to: string
  subject: string
  html: string
}) {
  const { data, error } = await resend.emails.send({
    from: 'hello@your-app.com',
    to,
    subject,
    html,
  })

  if (error) throw new Error(error.message)
  return data
}

Sending email must happen on the server side — in Server Actions, API routes, or Convex actions. Never call the Resend API from the browser.

Using React Email Templates

Install React Email:

pnpm add @react-email/components react-email

Create a template:

// src/emails/WelcomeEmail.tsx
import { Html, Body, Heading, Text, Button } from '@react-email/components'

export function WelcomeEmail({ name }: { name: string }) {
  return (
    <Html>
      <Body>
        <Heading>Welcome, {name}!</Heading>
        <Text>Thanks for joining. Get started below.</Text>
        <Button href="https://your-app.com/dashboard">
          Open Dashboard
        </Button>
      </Body>
    </Html>
  )
}

Send it with render:

import { render } from '@react-email/render'
import { WelcomeEmail } from '@/emails/WelcomeEmail'

const html = render(<WelcomeEmail name="Alex" />)
await sendEmail({ to: 'alex@example.com', subject: 'Welcome!', html })

From Address

To send from your own domain, verify it in the Resend dashboard under Domains, then update the from field in email.ts.

Free Tier Limits

Plan	Emails/month	Domains
Free	3,000	1
Pro	50,000+	Unlimited