Supercharge Your Rails App with Sidekiq: A Deep Dive into Background Job Processing

June 28, 2023

I recently posted about the top 10 Ruby gems for Ruby on Rails applications, which readers enjoyed, but each one doesn't go into much detail about how to get started with each gem. In this post, I'm going into more detail about Sidekiq: what it's useful for, what its features are, when to use it and what some of its drawbacks can be. Let's jump in!

My first proper encounter with Sidekiq was in generating an advertising report and sending it in an email from a full-stack application I developed for Joinative a couple of years ago. Emails can sometimes take a while to send, or the service that sends them can be unresponsive, or fail altogether. This is where background processes come into their own! By triggering a background job with Sidekiq and Redis, I was able to free up the thread and get a quick response to the user.

What is Sidekiq?

Sidekiq is a powerful background job processing gem for Ruby on Rails applications. It provides a simple and efficient way to perform time-consuming tasks asynchronously, freeing up your Rails app to handle other requests and improving overall performance. By freeing up the current thread, it lightens the load on the application, making the current request and other requests faster.

When to Use Sidekiq?

As mentioned above, Sidekiq is particularly useful in scenarios where you need to perform tasks that take a significant amount of time, such as sending emails, generating reports, processing large datasets, or making API calls. By offloading these tasks to Sidekiq workers, your Rails app can continue to handle other requests without getting bogged down by long-running processes.

Implementing Sidekiq in Your Rails App: To start using Sidekiq, you'll need to follow a few simple steps:

Step 1: Add Sidekiq to Your Gemfile and Install Dependencies

Open your Gemfile and add the following line:

gem 'sidekiq'

Save the file and run bundle install in your terminal to install Sidekiq and its dependencies.

Step 2: Set Up the Sidekiq Configuration

Sidekiq requires a Redis server to store job information. If you don't have Redis installed, make sure to install it on your system.

Next, create a config/sidekiq.yml file and configure Sidekiq to connect to your Redis server. Here's an example configuration:

  :url: redis://localhost:6379/0
  :url: <%= ENV['REDIS_URL'] %>

Adjust the Redis URL based on your Redis server configuration.

Step 3: Create a Sidekiq Worker

A Sidekiq worker is a Ruby class that defines the task you want to perform in the background. Create a new file called my_worker.rb in the app/workers directory. Here's an example of a simple Sidekiq worker:

class MyWorker
  include Sidekiq::Worker

  def perform(arg1, arg2)
    # Task logic goes here
    puts "Performing task with arguments: #{arg1} and #{arg2}"

In the perform method, you can add the logic for the task you want to perform asynchronously. The arguments you pass to the perform method will be available within the worker.

Step 4: Enqueue Jobs with Sidekiq

To enqueue a job, you can call the perform_async method on your Sidekiq worker class. For example:

MyWorker.perform_async('Hello', 'World')

This enqueues a job to be processed by Sidekiq. The worker's perform method will be called with the specified arguments. Alternatively, you can use the method perform_in, specifying an amount of time like 1.minute, 3.hours, or 5.days - you know, typical Rails stuff! This also calls the worker's perform method after the given delay and is perfect for enqueueing a job that doesn't need to be processed instantly.

Running Sidekiq:

To start Sidekiq, open a new terminal window, navigate to your Rails app directory, and run the following command:


This will start the Sidekiq process, which will continuously monitor the job queue and process jobs as they are enqueued.

Pros and Cons of Sidekiq:

Now that you have a good understanding of Sidekiq, let's take a look at some of its pros and cons:


  1. Scalability: Sidekiq can handle a large number of jobs concurrently, making it suitable for high-demand applications.
  2. Performance: By offloading time-consuming tasks to Sidekiq workers, your Rails app can respond faster and handle more requests.
  3. Retry Mechanism: Sidekiq automatically retries failed jobs, ensuring that no tasks are lost due to unexpected errors.
  4. Active Job Integration: Sidekiq seamlessly integrates with Rails' built-in Active Job framework, providing a unified interface for background job processing.
  5. User Interface: Sidekiq provides a tidy user interface where you, as a developer, can go to check the jobs that have been processed, as well as those that failed and retried. You can even manually trigger a retry if the situation calls for it.


  1. Setup and Infrastructure: Sidekiq requires a Redis server to store job information, which adds an additional layer of infrastructure complexity. You might incur extra costs in setting this up, for example with an extra Dyno on Heroku.
  2. Learning Curve: While Sidekiq offers powerful features, it may require some learning and familiarisation with its concepts and configuration options.
  3. Resource Utilisation: Running Sidekiq workers consumes system resources, so you need to ensure that your infrastructure can handle the additional load.


Congratulations! You've embarked on a journey into the world of Sidekiq and learned how to leverage its power to optimise background job processing in your Ruby on Rails application. We explored what Sidekiq is, when to use it, how to implement it, and even discussed its pros and cons.

With Sidekiq, you can now supercharge your Rails app, offloading time-consuming tasks to background workers and improving overall performance. So go ahead, give Sidekiq a try, and experience the joy of seamless background job processing in your Ruby on Rails application. If you face any challenges along the way, feel free to reach out to me for some guidance.

Are you looking to take the next step as a developer? Whether you're a new developer looking to break into the tech industry, or just looking to move up in terms of seniority, book a coaching session with me and I will help you achieve your goals or check out my available courses.