I'm building a Next.js app and need the simplest transactional email setup.

If you want the simplest transactional email setup for a Next.js app, the easiest path is usually:

Recommended stack

• Resend for sending email
• React Email for templating
• Next.js API route / server action to trigger sends

This is popular because it’s simple, developer-friendly, and works well with Next.js.

---

1) Install packages

npm install resend @react-email/components

If you want to build templates locally, also install React Email’s tooling:

npm install -D react-email

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2) Create a Resend account and API key

• Sign up at resend.com
• Create an API key
• Add it to .env.local

RESEND_API_KEY=your_api_key_here

---

3) Create a simple email template

Example: emails/welcome.tsx

import { Html, Body, Container, Heading, Text } from "@react-email/components";

export default function WelcomeEmail({ name }: { name: string }) {
  return (
    <Html>
      <Body>
        <Container>
          <Heading>Welcome, {name}!</Heading>
          <Text>Thanks for signing up.</Text>
        </Container>
      </Body>
    </Html>
  );
}

---

4) Send the email from a Next.js API route

Example for the App Router:

app/api/send-welcome/route.ts

import { Resend } from "resend";
import WelcomeEmail from "@/emails/welcome";
import { render } from "@react-email/components";

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

export async function POST(req: Request) {
  const { email, name } = await req.json();

  const html = await render(<WelcomeEmail name={name} />);

  const data = await resend.emails.send({
    from: "Your App <onboarding@yourdomain.com>",
    to: email,
    subject: "Welcome!",
    html,
  });

  return Response.json(data);
}

---

5) Call the endpoint from your app

await fetch("/api/send-welcome", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    email: "user@example.com",
    name: "Alex",
  }),
});

---

Notes

• You’ll need to verify a sending domain with Resend for production.
• For development, you can use Resend’s test/sandbox behavior depending on your setup.
• Keep email sending on the server only — never expose the API key in client code.

---

If you want even simpler

If you don’t care about templates yet, you can skip React Email and just send plain HTML:

await resend.emails.send({
  from: "Your App <onboarding@yourdomain.com>",
  to: email,
  subject: "Welcome!",
  html: "<p>Welcome, Alex!</p>",
});

---

If you want, I can give you a copy-paste Next.js starter for:

1. App Router
2. Pages Router
3. React Email + Resend
4. Nodemailer instead of Resend