Sending Emails with SMTP in Ruby

Send emails through AhaSend’s SMTP servers using Ruby’s versatile email solutions. This guide covers three popular approaches: the built-in net/smtp library, the powerful Mail gem, and Rails’ ActionMailer framework.

Ruby’s Email Flexibility: Ruby offers multiple excellent options for email sending, from lightweight standard library solutions to feature-rich frameworks - choose the one that best fits your application’s needs.

Prerequisites

Before you begin, ensure you have:

System Requirements

Ruby installed on your system (Download Ruby)
Ruby 2.7 or higher (recommended)
Basic knowledge of Ruby programming
Access to install gems (if using Mail gem or Rails)

AhaSend Setup

Domain verified in your AhaSend account
SMTP credentials created (username and password)
Access to your AhaSend dashboard for credential management

Need SMTP Credentials? If you haven’t created SMTP credentials yet, check out our SMTP Credentials guide for step-by-step instructions.

Ruby Email Solutions Overview

Ruby provides multiple excellent options for sending emails via SMTP:

Standard Library

Best for: Simple, lightweight email sending
Pros: No dependencies
Cons: Verbosity
Use case: Scripts

Mail Gem

Best for: non-Rails applications
Pros: High-level API
Cons: Ext. dependency
Use case: Standalone apps

ActionMailer (Rails)

Best for: Rails applications
Pros: Rails integration, templates, testing
Cons: Rails-specific
Use case: Web applications, MVC pattern

Connection Settings

Use these settings for all Ruby SMTP configurations with AhaSend:

Primary Server

Host: send.ahasend.com
Ports: 587 (recommended), 25, 2525
Security: STARTTLS
Authentication: Required

US Server

Host: send-us.ahasend.com
Ports: 587 (recommended), 25, 2525
Security: STARTTLS
Authentication: Required

Method 1: Using net/smtp (Standard Library)

The net/smtp library is part of Ruby’s standard library, offering a lightweight solution for sending emails without external dependencies.

Standard Library Advantage: net/smtp comes with Ruby - no gem installation required! Perfect for simple scripts and lightweight applications.

Basic Examples

require 'net/smtp'

def send_plain_text_email
  # SMTP server configuration
  smtp_settings = {
    address: 'send.ahasend.com',
    port: 587,
    domain: 'yourdomain.com',
    user_name: 'YOUR_SMTP_USERNAME',
    password: 'YOUR_SMTP_PASSWORD',
    authentication: 'plain',
    enable_starttls_auto: true
  }

  # Email content
  from_email = '[email protected]'
  to_email = '[email protected]'
  subject = 'Welcome to our platform!'
  body = 'Thanks for signing up. We\'re excited to have you!'

  # Construct the email message
  message = <<~MESSAGE_END
    From: Your Company <#{from_email}>
    To: #{to_email}
    Subject: #{subject}
    Date: #{Time.now.rfc2822}
    Content-Type: text/plain; charset=UTF-8

    #{body}
  MESSAGE_END

  # Send the email
  begin
    Net::SMTP.start(
      smtp_settings[:address],
      smtp_settings[:port],
      smtp_settings[:domain],
      smtp_settings[:user_name],
      smtp_settings[:password],
      smtp_settings[:authentication]
    ) do |smtp|
      smtp.enable_starttls
      smtp.send_message(message, from_email, to_email)
    end

    puts "Email sent successfully!"
  rescue => e
    puts "Failed to send email: #{e.message}"
  end
end

# Send the email
send_plain_text_email

Method 2: Using the Mail Gem

The Mail gem provides a high-level, Ruby-style interface for email handling with rich features like attachments, multipart messages, and template support.

Mail Gem Benefits: Clean API, automatic MIME handling, built-in attachment support, and excellent template integration. Perfect for complex email applications.

Installation

Add the Mail gem to your project:

# Add to your Gemfile
gem 'mail'

# Then run:
bundle install

Basic Examples

require 'mail'

# Configure Mail gem defaults
Mail.defaults do
  delivery_method :smtp, {
    address: 'send.ahasend.com',
    port: 587,
    user_name: 'YOUR_SMTP_USERNAME',
    password: 'YOUR_SMTP_PASSWORD',
    authentication: 'plain',
    enable_starttls_auto: true
  }
end

def send_plain_text_email
  begin
    mail = Mail.new do
      from     '[email protected]'
      to       '[email protected]'
      subject  'Welcome to our platform!'
      body     'Thanks for signing up. We\'re excited to have you!'
    end

    mail.deliver!
    puts "Email sent successfully!"
  rescue => e
    puts "Failed to send email: #{e.message}"
  end
end

send_plain_text_email

Advanced Mail Gem Features

require 'mail'

# Configure Mail gem defaults
Mail.defaults do
  delivery_method :smtp, {
    address: 'send.ahasend.com',
    port: 587,
    user_name: 'YOUR_SMTP_USERNAME',
    password: 'YOUR_SMTP_PASSWORD',
    authentication: 'plain',
    enable_starttls_auto: true
  }
end

def send_email_with_special_headers
  begin
    mail = Mail.new do
      from     '[email protected]'
      to       ['[email protected]', '[email protected]']
      cc       '[email protected]'
      bcc      '[email protected]'
      subject  'Product Updates with Tracking'

      # Add AhaSend special headers
      header['ahasend-track-opens'] = 'true'
      header['ahasend-track-clicks'] = 'true'
      header['ahasend-tags'] = 'product-update,newsletter,ruby'
      header['ahasend-message-retention'] = '30'
      header['ahasend-message-data-retention'] = '7'

      text_part do
        body 'Check out our latest features at https://yourdomain.com/features'
      end

      html_part do
        content_type 'text/html; charset=UTF-8'
        body <<~HTML
          <html>
          <body>
            <h1>Product Updates</h1>
            <p>Check out our <a href="https://yourdomain.com/features">latest features</a>!</p>
            <p>This email has tracking enabled and custom tags.</p>
          </body>
          </html>
        HTML
      end
    end

    mail.deliver!
    puts "Email sent with special headers!"
  rescue => e
    puts "Failed to send email: #{e.message}"
  end
end

send_email_with_special_headers

Method 3: Using ActionMailer (Rails)

ActionMailer is part of Ruby on Rails and provides a comprehensive email solution with MVC patterns, templates, and excellent testing support.

Rails Integration: ActionMailer seamlessly integrates with Rails applications, providing view templates, internationalization, background job support, and comprehensive testing utilities.

Configuration

Configure your SMTP settings in the appropriate environment file:

# Production environment configuration
Rails.application.configure do
  # Email configuration
  config.action_mailer.delivery_method = :smtp
  config.action_mailer.smtp_settings = {
    address: 'send.ahasend.com',
    port: 587,
    domain: 'yourdomain.com',
    user_name: ENV['SMTP_USERNAME'],
    password: ENV['SMTP_PASSWORD'],
    authentication: 'plain',
    enable_starttls_auto: true
  }

  # Set default host for URL generation
  config.action_mailer.default_url_options = {
    host: 'yourdomain.com',
    protocol: 'https'
  }
end

Basic Mailer Setup

class UserMailer < ActionMailer::Base
  default from: '[email protected]'

  def welcome_email(user)
    @user = user
    @url = root_url

    mail(
      to: user.email,
      subject: 'Welcome to our platform!'
    )
  end

  def notification_email(user, title, message)
    @user = user
    @title = title
    @message = message

    # Add AhaSend special headers
    headers['ahasend-track-opens'] = 'true'
    headers['ahasend-track-clicks'] = 'true'
    headers['ahasend-tags'] = 'notification,rails'

    mail(
      to: user.email,
      subject: title
    )
  end
end

Testing with Sandbox Mode

Use sandbox mode to safely test your Ruby email integration across all methods:

require 'net/smtp'

def send_sandbox_test
  smtp_settings = {
    address: 'send.ahasend.com',
    port: 587,
    domain: 'yourdomain.com',
    user_name: 'YOUR_SMTP_USERNAME',
    password: 'YOUR_SMTP_PASSWORD',
    authentication: 'plain'
  }

  message = <<~MESSAGE_END
    From: [email protected]
    To: [email protected]
    Subject: Sandbox Test Email
    AhaSend-Sandbox: true
    AhaSend-Sandbox-Result: deliver

    This email is sent in sandbox mode for testing.
  MESSAGE_END

  begin
    Net::SMTP.start(
      smtp_settings[:address], smtp_settings[:port], smtp_settings[:domain],
      smtp_settings[:user_name], smtp_settings[:password], smtp_settings[:authentication]
    ) do |smtp|
      smtp.enable_starttls
      smtp.send_message(message, '[email protected]', '[email protected]')
    end

    puts "Sandbox email sent successfully!"
  rescue => e
    puts "Failed to send sandbox email: #{e.message}"
  end
end

send_sandbox_test

Sandbox Benefits: Emails sent in sandbox mode are free, trigger webhooks normally, and never actually deliver to recipients - perfect for development and testing.

Resources

Ruby net/smtp Documentation

Official net/smtp library documentation

Mail Gem Documentation

Comprehensive Mail gem guide and examples

ActionMailer Guide

Official Rails ActionMailer documentation

AhaSend Support

Get help from our engineering team

Getting Started

Sending with SMTP

Sending with the API

Email Tracking

Integrations

Data Retention

Security

Scaling up

Sending emails in Ruby

Sending Emails with SMTP in Ruby

Prerequisites

Ruby Email Solutions Overview

Standard Library

Mail Gem

ActionMailer (Rails)

Connection Settings

Primary Server

US Server

Method 1: Using net/smtp (Standard Library)

Basic Examples

Method 2: Using the Mail Gem

Installation

Basic Examples

Advanced Mail Gem Features

Method 3: Using ActionMailer (Rails)

Configuration

Basic Mailer Setup

Testing with Sandbox Mode

Resources

Ruby net/smtp Documentation

Mail Gem Documentation

ActionMailer Guide

AhaSend Support

Getting Started

Sending with SMTP

Sending with the API

Email Tracking

Integrations

Data Retention

Security

Scaling up

​Sending Emails with SMTP in Ruby

​Prerequisites

​Ruby Email Solutions Overview

Standard Library

Mail Gem

ActionMailer (Rails)

​Connection Settings

Primary Server

US Server

​Method 1: Using net/smtp (Standard Library)

​Basic Examples

​Method 2: Using the Mail Gem

​Installation

​Basic Examples

​Advanced Mail Gem Features

​Method 3: Using ActionMailer (Rails)

​Configuration

​Basic Mailer Setup

​Testing with Sandbox Mode

​Resources

Ruby net/smtp Documentation

Mail Gem Documentation

ActionMailer Guide

AhaSend Support

Sending Emails with SMTP in Ruby

Prerequisites

Ruby Email Solutions Overview

Connection Settings

Method 1: Using net/smtp (Standard Library)

Basic Examples

Method 2: Using the Mail Gem

Installation

Basic Examples

Advanced Mail Gem Features

Method 3: Using ActionMailer (Rails)

Configuration

Basic Mailer Setup

Testing with Sandbox Mode

Resources