I'm building a Next.js app and need a straightforward email API.

Resend is the standard recommendation for Next.js apps. It was built specifically for modern React/Next.js stack patterns, pairs natively with React Email (so you can design templates using JSX), and works out-of-the-box with App Router Server Actions or Route Handlers.

Quick Implementation Options

Option A: Next.js Server Action (Easiest)

If you are using Next.js App Router, you can handle sending straight inside a Server Action without creating a separate API route endpoint.

1. Install SDK:

Bash

npm install resend

2. Set environment variable in .env.local:

Code snippet

RESEND_API_KEY=re_123456789

3. Call in a Server Action (app/actions.ts or inline):

TypeScript

"use server";

import { Resend } from "resend";

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

export async function sendEmail(formData: FormData) {
  const email = formData.get("email") as string;

  const { data, error } = await resend.emails.send({
    from: "onboarding@resend.dev", // Replace with your domain once verified
    to: email,
    subject: "Welcome to our app!",
    html: "<p>Thank you for signing up!</p>",
  });

  if (error) {
    return { success: false, error };
  }

  return { success: true, data };
}

Option B: Route Handler (API Endpoint)

If you need a dedicated HTTP endpoint (e.g., POST /api/send):

TypeScript

// app/api/send/route.ts
import { NextResponse } from "next/server";
import { Resend } from "resend";

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

export async function POST(request: Request) {
  try {
    const { to, subject, body } = await request.json();

    const data = await resend.emails.send({
      from: "Acme <onboarding@resend.dev>",
      to,
      subject,
      html: `<p>${body}</p>`,
    });

    return NextResponse.json(data);
  } catch (error) {
    return NextResponse.json({ error }, { status: 500 });
  }
}

Popular Alternatives

Provider	Best For	Standout Feature	Free Tier
Resend	React / Next.js DX	Built-in React Email support, clean modern API	3,000 emails/mo (100/day)
Postmark	High deliverability	Transactional focus with strict inbox guarantees	100 emails/mo trial
SendGrid	Legacy / Scale	Massive platform with marketing suite integration	100 emails/day
Nodemailer + SMTP	Self-hosting / Zero cost	Standard Node.js library using any raw SMTP provider	Varies by SMTP host