Deno Mailer

Lightweight Deno SMTP mailer with flexible configuration and formatting.

Features

• Simple SMTP transport: create transporter and send emails with minimal setup
• Connection pooling support: reuse SMTP clients with configurable pool limits
• DKIM signing support: sign outgoing messages with RSA private key
• Flexible recipients: supports string, object, and mixed recipient formats
• Rich message content: plain text, HTML, mixed body, and custom headers
• Attachments and inline media: supports file attachments and embedded images
• Transfer encodings: base64, 7bit, quoted-printable for attachment content
• Calendar invitations: generates ICS calendar payload for meeting invites
• Structured send result: returns message id, envelope, accepted, rejected, and response
• Zero external runtime deps: built with Deno native capabilities

Installation

# Install package from JSR.
deno add jsr:@neabyte/deno-mailer

Quick Start

// Import package entry.
import mailer from '@neabyte/deno-mailer'

// Create SMTP transporter instance.
const transporter = mailer.transporter({
  host: 'smtp.domain.com',
  port: 587,
  secure: false,
  auth: {
    type: 'password',
    user: 'user@domain.com',
    pass: 'password'
  }
})

// Send one email with text and HTML parts.
const result = await transporter.send({
  from: '"John Doe" <john.doe@example.com>',
  to: 'recipient@domain.com',
  subject: 'Test Email',
  text: 'This is a test email',
  html: '<b>This is a test email</b>'
})
console.log(result.messageId)

Build and Check

# Run format, lint, and type-check.
deno task check

Test

# Copy env template for SMTP integration tests.
cp .env.example .env

# Set ETHEREAL_USER and ETHEREAL_PASS in .env, then run test suite.
deno task test

# Alternative: export credentials in shell, then run test suite.
export ETHEREAL_USER=your-ethereal-username
export ETHEREAL_PASS=your-ethereal-password

# Optional: run OAuth2 integration test too.
export SMTP_OAUTH2_ACCESS_TOKEN=your-oauth2-access-token
export RUN_OAUTH2_SMTP_TEST=true

# Optional: run secure TLS (port 465) integration test too.
export RUN_SECURE_SMTP_TEST=true

# Run full unit and integration tests.
deno task test

Reference

• USAGE.md: complete API usage, configuration, and troubleshooting
• CHANGELOG.md: release history and notable changes

Contributing

Contributions are welcome. Open an issue or submit a pull request.

License

This project is licensed under the MIT license. See LICENSE.