Background email delivery in Ruby on Rails

Introduction

Sending emails can take time and slow down your app. Background email delivery lets your app send emails without making users wait.

When a user signs up and you want to send a welcome email without delay.

When sending password reset emails quickly without freezing the page.

When sending newsletters or bulk emails without slowing down your app.

When you want to improve user experience by handling email sending quietly in the background.

Syntax

Ruby on Rails

class UserMailer < ApplicationMailer
  def welcome_email(user)
    @user = user
    mail(to: @user.email, subject: 'Welcome!')
  end
end

# To send email in background
UserMailer.welcome_email(user).deliver_later

deliver_later tells Rails to send the email using a background job.

You need to have a background job system set up, like Sidekiq or the default Async adapter.

Examples

Sends email immediately, blocking the app until done.

Ruby on Rails

UserMailer.welcome_email(user).deliver_now

Sends email in the background, so the app keeps running smoothly.

Ruby on Rails

UserMailer.welcome_email(user).deliver_later

Sends email after a delay of 5 minutes.

Ruby on Rails

UserMailer.welcome_email(user).deliver_later(wait: 5.minutes)

Sample Program

This example shows how to define a mailer and send an email in the background. The app does not wait for the email to send and prints a message immediately.

Ruby on Rails

class UserMailer < ApplicationMailer
  def welcome_email(user)
    @user = user
    mail(to: @user.email, subject: 'Welcome to Our App')
  end
end

# In a controller or job
user = User.new(email: '[e-mail]')
# Simulate saving user

# Send welcome email in background
UserMailer.welcome_email(user).deliver_later

puts 'Email job queued, app continues running.'

Important Notes

Make sure your app has a background job processor configured to handle deliver_later calls.

Check your development logs to see when emails are actually sent.

Background jobs improve user experience by avoiding delays during email sending.

Summary

Background email delivery sends emails without blocking your app.

Use deliver_later to queue emails for background sending.

Set up a background job system to handle email jobs properly.