Top 7 Ruby on Rails Gems for Web Apps in 2025

Are you a Ruby on Rails developer looking for the most reliable and popular ruby gems to speed up development and scale your app?

You’re in the right place!

This might be the one article you need to read today.

Whether you're building an MVP or maintaining a mature Rails application, the right gems can save development time, reduce bugs, and make your app more scalable from day one.

At RailsFactory, we've specialized in Ruby on Rails for over 18 years, helping startups and enterprises alike deliver reliable applications. Our team of seasoned RoR developers works with Rails every day, relying on a carefully chosen set of gems to streamline workflows, enforce best practices, and ensure maintainability at scale.

In this article, we’ve curated a list of the most trusted and widely used Ruby on Rails gems you should consider this year. Whether you're handling authentication, background jobs, or improving code quality, these gems are battle-tested and actively maintained by the Rails community.

Let’s take a closer look at the list of most popular ruby gems powering modern Rails applications.

Pry

Total Downloads: 513,308k (as of May 2025)

GitHub Stars: 6.8k

What it does:

Pry is a powerful alternative to Ruby’s default IRB shell that enhances the Rails console and debugging experience. It offers runtime introspection, syntax highlighting, and the ability to step into live code execution. Developers can pause the app with binding.pry, inspect the current state, and test methods interactively, making debugging more precise and dynamic.

Why it matters:

Pry dramatically improves debugging efficiency. It eliminates the need for scattered puts statements or full app reloads by letting developers inspect variables and modify logic on the fly. This interactive workflow speeds up development, surfaces bugs earlier, and helps teams ship more reliable code with less friction.

Use cases:

Insert breakpoints with binding.pry to pause execution

Inspect variable values and object states in real time

Manually call methods and test changes on the fly

Navigate the call stack using commands like whereami and cd

Modify or retry logic interactively during a paused session

Installation:

Add the following gems to your Gemfile:

Then run:

Use binding.pry in your code to start debugging.

Devise

Total Downloads: 235,462k (as of May 2025)

GitHub Stars: 24.2k

What it does:

Devise is a flexible and full-featured authentication solution for Rails applications. It provides a complete suite of modules to manage everything from user registration and session tracking to password recovery, confirmation emails, and even two-factor authentication, all with minimal setup.

Why it matters:

Devise streamlines secure user authentication at scale. It eliminates the need to build access control from scratch, giving teams out-of-the-box modules that are battle-tested and widely adopted. Its modular approach ensures you only use what you need, helping keep apps performant, maintainable, and secure as they grow.

Use cases:

User sign-up/sign-in flows with secure session handling

Password recovery via secure email links

Email confirmation and account locking on failed login attempts

Multi-factor authentication for added security

Scalable access control for multi-role or multi-user applications

Installation:

Add Devise to your Gemfile:

Install the gem:

Set up Devise:

Generate your User model with Devise:

RSpec

Total Downloads: 873,328k (as of May 2025)

GitHub Stars: 5.2k

What it does:

RSpec is the go-to testing framework for Ruby on Rails. It offers a clean and expressive DSL for writing unit, integration, and system tests. It also integrates well with tools like Capybara, FactoryBot, and SimpleCov, making it central to most Rails testing stacks.

Why it matters:

RSpec helps teams build reliable and scalable applications by enabling behavior-driven testing. Its readable syntax makes it easier for developers to write and maintain test cases, catch bugs early, and confidently refactor code, all while reducing the need for manual testing.

Use cases:

Creating fast and isolated model specs to verify business logic

Simulating complex user interactions with feature specs and Capybara

Setting up factories (via FactoryBot) for reusable test data

Automating test coverage audits with SimpleCov reports

Running specs in CI pipelines to catch regressions before deployment

Installation Steps:

Add the gem to your Gemfile:

Install it:

Set up RSpec in your Rails app:

This sets up the necessary configuration files and directories for RSpec in your Rails application.

RuboCop

Total Downloads: 541,928k (as of May 2025)

GitHub Stars: 12.7k

What it does:

RuboCop is a static code analyzer and linter for Ruby. It enforces consistent coding standards and Ruby style guide rules across the codebase. With built-in auto-correction, it helps teams clean up code quickly while reducing manual review effort.

Why it matters:

For teams working on scalable Rails apps, RuboCop is vital for maintaining healthy codebases over time. It improves readability and enforces uniform coding practices. By automatically formatting code and flagging violations early, it also reduces technical debt and streamlines code reviews.

Use cases:

Enforcing uniform Ruby and Rails coding conventions

Catching code smells, unused variables, or risky syntax

Auto-correcting style violations across large codebases

Integrating with CI/CD to prevent poorly formatted code merges

Tailoring custom rules for organization-specific coding standards

Installation Steps:

Add to your Gemfile

Install the gem:

Initialize a config file (optional but recommended):

Run RuboCop:

Pundit

Total Downloads: 80,685k (as of May 2025)

GitHub Stars: 8.4k

What it does:

Pundit uses plain Ruby classes called policies to encapsulate authorization logic for each model. This promotes a clear separation of concerns and makes permissions easier to test, audit, and reason about on a per-resource basis. It’s designed to support fine-grained, scalable access control in Rails apps of any size.

Why it matters:

For a growing Rails application that needs clean and reliable authorization logic, Pundit offers a modular, maintainable solution. By organizing access rules into policy files, it keeps controllers thin and business logic decoupled. This structure makes it easier to test and extend permissions without sacrificing code clarity or performance.

Use cases:

Defining resource-specific access control (e.g., only authors can edit their own posts)

Replacing hard-coded conditionals with centralized policy files

Supporting custom roles and conditional permissions

Testing authorization logic in isolation

Scaling access control as teams and features expand

Installation Steps:

Add Pundit to your Gemfile:

Run:

Include Pundit in your application controller:

(Optional) Generate the install files:

Define a policy for your model (e.g., PostPolicy):

Use authorize in your controller actions:

Sidekiq

Total Downloads: 266,624k (as of May 2025)

GitHub Stars: 13.3k

What it does

Sidekiq is a high-performance background job processor for Rails apps. Unlike traditional forking models, it uses threads to manage thousands of concurrent jobs with lower memory overhead. Whether it’s handling emails, bulk data processing, or third-party API syncs, Sidekiq runs these tasks in the background to keep your app fast and responsive.

Why it matters

Sidekiq is an essential tool for offloading time-consuming processes. Its thread-based approach allows efficient job handling without spinning up multiple processes, saving both memory and time. By delegating heavy operations like file processing, notifications, or data syncs to background workers, you ensure your main application stays stable, especially under load.

Use Cases

Delivering emails without slowing down user requests

Importing CSV or large external datasets

Calling third-party APIs asynchronously

Scheduling background clean-up or maintenance jobs

Processing reports or long-running tasks in the background

Installation Steps

Add Sidekiq to your Gemfile:

Run bundle install:

Create a worker:

Define your job logic in the worker file:

Start the Sidekiq process:

Kaminari

Total Downloads: 218,424 k (as of May 2025)

GitHub Stars: 8.6k

What it does

Kaminari is a versatile pagination gem for Rails, built to handle everything from simple page splits to custom pagination UIs. It’s compatible with ActiveRecord, Mongoid, and other ORMs, and supports both classic and infinite scrolling interfaces. Its flexibility allows for easy customization of pagination behavior and views.

Why it matters

For a growing Rails app, delivering paginated content is crucial for performance and UX. Kaminari helps break large datasets into manageable chunks, reducing load times and improving response efficiency. Its modular design lets users fine-tune pagination logic without cluttering your controllers or views, keeping your code clean and scalable.

Use Cases

Paginating blog posts, products, user lists, etc.

Customizing pagination UI to match brand styling

Supporting endless scrolling or “Load More” buttons

Paginating API responses for mobile or frontend apps

Efficient rendering of large data tables with minimal memory

Installation Steps:

Add the gem to your Gemfile:

Run bundle install:

Use it in your controller:

Add the pagination view in your template:

Generate views to customize pagination UI:

Conclusion

Employing the right Ruby gems isn’t just about saving time, it’s about building smarter from the start. While the world of gems is vast, the ones we’ve covered here are trusted for a reason: they solve real problems, streamline development, and help your Rails app scale without turning into a tangled mess of code.

That said, no gem is a magic fix. They’ll take you most of the way, but the last mile still needs experience, context, and a bit of Rails craftsmanship. With the right team of skilled Rails experts by your side, it can make all the difference.

If you're in the thick of a complex Rails upgrade, building something ambitious, or just need a fresh pair of eyes on your codebase, we’re here to help. Rails is what we do. Let’s make it work even better for you.