Send email from Next.js over SMTP

Send from a Next.js Route Handler with Nodemailer pointed at Unitpost SMTP. Keep the API key on the server — never in a Client Component.

1. 1

   Install Nodemailer

   Shell

   npm install nodemailer
   npm install -D @types/nodemailer

2. 2

   Create a Route Handler

   Server-only. The from address must be on a verified domain.

   TypeScript

   import nodemailer from "nodemailer";
   import { NextResponse } from "next/server";
   
   const transporter = nodemailer.createTransport({
     host: "smtp.unitpost.com",
     port: 587,
     secure: false,
     requireTLS: true,
     auth: {
       user: "unitpost",
       pass: process.env.UNITPOST_API_KEY,
     },
   });
   
   export async function POST() {
     await transporter.sendMail({
       from: "you@yourdomain.com",
       to: "customer@example.com",
       subject: "Hello from Next.js",
       html: "<p>Sent via SMTP.</p>",
     });
     return NextResponse.json({ ok: true });
   }

3. 3

   Verify delivery

   Check Activity. Same transport as the Nodemailer guide — this page is the Next.js wiring.