# Nodemailer

Send plain-text and HTML email from your Node.js application.

Before you begin, verify a sending domain and create an [API key](https://usesendy.com/docs/authentication). Run this integration on your application server.

## Install Nodemailer

In your Node.js project, install the package:

Install · terminal

```
npm install nodemailer
```

## Send an email

Save this example as `send-email.mjs`:

send-email.mjs

```
import nodemailer from "nodemailer";

const transport = nodemailer.createTransport({
  host: "smtp.usesendy.com",
  port: 2525,
  secure: false,
  requireTLS: true,
  auth: {
    user: "apikey",
    pass: "API_KEY",
  },
});

const result = await transport.sendMail({
  from: "My App <noreply@example.com>",
  to: "recipient@example.com",
  subject: "Welcome",
  text: "Your account is ready.",
  html: "<h1>Welcome</h1><p>Your account is ready.</p>",
});

console.log(result.response);
```

Replace `API_KEY` with your full API key, the sender with an address on your verified domain, and the recipient with your test address. Keep the key in your server’s secret configuration.

`secure: false` selects STARTTLS instead of implicit TLS. `requireTLS: true` requires the encrypted upgrade. See [Nodemailer SMTP options](https://nodemailer.com/smtp).

Run the example:

Send · terminal

```
node send-email.mjs
```

## Retry safely

Set `headers` on the `sendMail` message to provide an idempotency key:

Message options

```
headers: {
  "Sendy-Idempotency-Key": "welcome/user-123",
},
```

Use a key unique to the logical email and reuse it for retries. Matching submissions return the original job IDs without reserving credit again. Generated dates and message IDs can change, but other MIME bytes must match. If you send multipart messages or attachments, preserve the composed raw message so retries retain their boundaries and encoding. See [SMTP idempotency behavior](https://usesendy.com/docs/smtp) for key limits and conflict responses.

## Check the result

The SMTP response contains the queued job IDs:

Example response

```
250 2.0.0 Queued jobs 123
```

This confirms that Sendy queued the email. Check [Emails](https://usesendy.com/emails) or [Get email status](https://usesendy.com/docs/api/email-status) to follow delivery. For attachments and message limits, see [SMTP](https://usesendy.com/docs/smtp).