How to send email from Express

You can send email from an Express.js app using libraries like Nodemailer (SMTP-based) or modern email APIs (SendLayer, Resend, Postmark). The simplest approach is to set up a route in Express that calls Nodemailer with your credentials, or use an API provider for better deliverability and security.

🔧 Using Nodemailer (SMTP)

Install dependencies

bash

npm install express nodemailer body-parser dotenv

Configure transporter

js

const nodemailer = require("nodemailer");

const transporter = nodemailer.createTransport({

• service: "gmail", // or outlook, yahoo, etc.
• auth: {
• user: process.env.EMAIL_USER,
• pass: process.env.EMAIL_PASS

}

});

Create route in Express

js

app.post("/send-email", async (req, res) => {

const { to, subject, text } = req.body;

try {

• await transporter.sendMail({ from: process.env.EMAIL_USER, to, subject, text });

res.send("Email sent successfully!");

} catch (err) {

res.status(500).send("Error sending email");

}

});

🌐 Using Email APIs (No SMTP)

If you don’t want to deal with SMTP, use an API provider:

SendLayer / Resend / Postmark / SendGrid

Sign up and get an API key.

Verify your domain (SPF/DKIM setup).

Use fetch or axios in your Express route to call their HTTPS endpoint.

js

const axios = require("axios");

app.post("/send-email", async (req, res) => {

const { to, subject, text } = req.body;

try {

await axios.post("https://api.resend.com/emails", {

• from: "you@yourdomain.com",

to,

subject,

text

}, {

• headers: { Authorization: Bearer ${process.env.RESEND_API_KEY} }

});

res.send("Email sent via API!");

} catch (err) {

res.status(500).send("Error sending email");

}

});

⚠️ Best Practices

Use environment variables (.env) for credentials.

Never expose API keys in client-side code.

Set up SPF/DKIM/DMARC for your domain to avoid spam folders.

Log and monitor delivery status with webhooks or dashboards.

✅ When to Choose What

• Quick setup, small apps: Nodemailer with Gmail/Outlook.

• Scalable, production-ready apps: API providers like Resend, Postmark, or SendGrid.

• Cost-sensitive, high-volume apps: Amazon SES (requires more setup).