As a Ruby on Rails developer, it’s important to harness the power of various gems to enhance the development process, improve code quality, and ensure security. In this article, you will review some of the must-have gems for your Ruby on Rails application.

These gems offer features for auditing, code analysis, code quality improvement, testing, and debugging.

Essential Gems for Ruby on Rails Applications

1. Bundler Audit

Bundler Audit is a gem that scans your application’s dependencies for known security vulnerabilities. It checks your Gemfile.lock against a vulnerability database and alerts you if any of your gems have known vulnerabilities. By using Bundler Audit, you can proactively address security issues and keep your application secure.

Its main features include:

  • Checks for vulnerable versions of gems in Gemfile.lock
  • Checks for insecure gem sources (http:// and git://)
  • Allows ignoring certain advisories that have been manually worked around
  • Prints advisory information

Bundler Audit can be added locally, or it is best to add it to your Gemfile for CI/CD integration.

gem ‘bundler-audit’

2. FriendlyId

FriendlyId is a gem that allows you to create custom, user-friendly URLs for your Rails models. It replaces the default numeric IDs with human-readable slugs, improving the SEO-friendliness and user experience of your application. With FriendlyId, you can easily generate slugs for models based on attributes or custom logic.

gem ‘friendly_id’

3. Bullet

Bullet is a gem that helps you identify and optimize unnecessary database queries. It provides N+1 query detection, unused eager loading detection, and other performance optimizations. By using Bullet, you can improve the efficiency of your application and ensure that database queries are optimized. Add this to your Gemfile under the development group.

gem 'bullet', group: 'development'

4. Reek

Reek is a gem that analyzes your codebase and detects code smells or design issues. It helps you identify areas where you can simplify and refactor your code to improve its readability and maintainability. By running Reek on your code, you can ensure that your application adheres to best practices and is easier to maintain in the long run.

gem ‘reek’

5. Rubocop

Rubocop is a widely used gem for enforcing consistent coding styles and best practices in your Rails application. It provides a set of rules and guidelines that can be customized to match your project’s preferences. By using Rubocop, you can ensure that your codebase is clean, readable, and adheres to commonly accepted coding conventions.

gem 'rubocop', require: false

6. rails_best_practices

rails_best_practices is a gem that analyzes your Rails application and provides recommendations for improving your code based on best practices. It helps you identify potential performance issues, security vulnerabilities, and design flaws. By using rails_best_practices, you can ensure that your application follows established Rails conventions and guidelines.

gem ‘rails_best_practices’

7. Brakeman

Brakeman is a gem that scans your Ruby on Rails application for security vulnerabilities. It examines your codebase for potential security risks such as SQL injections, cross-site scripting, and other common vulnerabilities. By using Brakeman, you can identify and address security issues early in the development process, reducing the risk of security breaches.

group :development do
  gem 'brakeman'

8. RSpec-rails

RSpec-rails is a popular gem for behavior-driven development (BDD) and testing in Ruby on Rails. It provides a powerful and expressive syntax for writing tests, making it easier to define and document the behavior of your application. By using RSpec-rails, you can ensure the reliability and correctness of your code through effective testing practices.

group :development, :test do
  gem 'rspec-rails', '~> 6.0.0'

9. Pry

Pry is a feature-rich gem that enhances the debugging experience in Ruby on Rails. It provides a powerful REPL (Read-Eval-Print Loop) environment with advanced features such as syntax highlighting, code introspection, and breakpoint debugging. By using Pry, you can interactively debug your application, inspect variables, and diagnose and fix issues more effectively.

group :development, :test do
  gem 'pry’

10. Traceroute

Traceroute is a gem that helps you understand the flow of your Rails application and identify potential performance bottlenecks. It provides detailed information about the time taken by each middleware and controller action, allowing you to pinpoint areas that require optimization. By using Traceroute, you can optimize the performance of your application and provide a smooth user experience.

gem traceroute


Incorporating these 10 essential gems into your Ruby on Rails applications can significantly improve your development workflow, enhance code quality, and boost security. From optimizing database queries to enforcing coding standards and conducting thorough testing, these gems offer developers a wide range of benefits.

Note that many established Rails projects run a combination of Brakeman, Rspec-rails, and Bundler Audit in their CI/CD pipeline builds as a means to cover security and vulnerability by:

  • Brakeman – will scan and analyze your code for any possible dangerous calls or expressions
  • Rspec-rails – will run your test cases against the codebase
  • Bundler Audit – will find dependencies that have known vulnerabilities

Experiment with all or some of these gems in your new projects and experience the advantages they bring to your Ruby on Rails development journey. Or bring your established projects up to speed. Happy coding!

Lee Sheppard

Lee is an Agile certified full stack Ruby on Rails developer. With over six years in the tech industry he enjoys teaching, coaching Agile, and mentoring others. Lee also speaks at tech related events and has a background in design and illustration.