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10 Common Rails Programming Mistakes You Should Avoid

kokou adzo



macbook pro on black wooden table

Ruby on Rails, commonly referred to as “Rails,” has genuinely shifted the paradigm of web application development, emphasizing its “convention over configuration” (CoC) and “don’t repeat yourself” (DRY) principles. More than 3.7 million active websites employ Ruby on Rails as a framework.

This framework has empowered every Ruby on Rails development company to craft strong, scalable applications with greater simplicity. Yet, given the plethora of features Rails offers, even the most proficient developers can sometimes stumble.

Here are 10 Typical Rails Programming Oversights and Their Remedies:

1.   Overusing Callbacks

The Mistake: Rails equips developers with robust callback functionalities. This facilitates the automation of specific events during an object’s life journey. Although they streamline some processes, an over-dependence can create labyrinthine models.

How to Avoid: Intertwining multiple callbacks within a single model might generate conflicts or sporadic activations. As this complexity escalates, maintaining the model becomes a daunting task.

The ideal approach? Abide by the Single Responsibility Principle, ensuring each class has a singular change reason. If a callback diverges from the model’s main function, perhaps it’s more apt for a service object or decorator.

2.   Ignoring the Database

The Mistake: Rails boasts impeccable database integration, often making underlying operations feel invisible. But this seamless experience can, at times, lead to unoptimized queries or decreased speed.

How to Avoid: Although Rails does the heavy lifting in bridging database peculiarities, understanding the backend remains crucial. Watch for pitfalls like the N+1 queries.

Tools like the ‘bullet’ gem can assist in flagging such concerns. Moreover, acquaint yourself with database indexing mechanics. Periodically scour logs for sluggish queries to fine-tune your database performance.

3.   Not Writing Tests or Ignoring Failing Tests

The Mistake: Tests in Rails offer a blueprint of the application’s functionality, providing a cushion during reshaping tasks. However, an occasional disregard for testing or turning a blind eye to failures can happen.

How to Avoid: While crafting apps without tests might seem expedient initially, it seeds potential challenges down the line. Embrace testing tools like RSpec and MiniTest, aiming for exhaustive test coverage. Leverage tools like SimpleCov for assessment, and prioritize rectifying failed tests.

4.   Bypassing Validations

The Mistake: Rails’ sturdy validation mechanism is often a developer’s ally. However, methods like update_attribute can sidestep these validations, potentially causing data anomalies.

How to Avoid: Data sanctity is non-negotiable. Rails validations ensure data consistency before it nestles into the database. Fully comprehend the nuances of methods like update and update_attribute. Unless bypassing validations is unequivocally necessary, stick with the conventional path, and document exceptions rigorously.

5.   Not Understanding the Asset Pipeline

The Mistake: Rails’ asset pipeline is engineered to optimize assets such as CSS and JavaScript. A misconfiguration can hamper asset delivery or impact performance adversely.

How to Avoid: Dive deep into the workings of the asset pipeline to prevent deployment hiccups. Ensure a rigorous precompilation regimen for the production phase. Harness Rails helpers like image_tag for seamless asset linkage post-optimization.

6.   Not Using Background Jobs for Time-Consuming Tasks

The Mistake: Keeping users waiting during real-time tasks, like email dispatches, is hardly the best user experience.

How to Avoid: Web applications should be synonymous with responsiveness. Offload demanding tasks like data computation or emailing to background jobs. Tools like Sidekiq or Resque are tailor-made for these operations, ensuring your primary app remains agile and user-centric.

7.   Going Overboard with Gems

The Mistake: While the Rails ecosystem boasts a rich set of gems, indiscriminately adding them can bloat the application and introduce potential security risks.

How to Avoid: Gems are fantastic, offering shortcuts to solve pesky problems. But more isn’t always better. Each gem you slide into your application’s pocket is like adding another link to a chain – it could be the weak one.

Before you decide to use a gem, stop and think. Look into how often it’s updated, its support community, and how well it’s maintained.

For a hand in spotting vulnerabilities, tools like Bundler-audit can be your lookout.

8.   Not Indexing Database Columns

The Mistake: For optimal performance, database columns involved in searches or joins need indexing. Ignoring this can drastically slow operations down.

How to Avoid: As your application matures and bulks up with data, it’s crucial that the database stays agile. Think of indexing as giving your database a map, instead of making it wander around lost.

Prioritize columns involved in joins or search operations. And if you’re ever unsure, there are tools like rails_db that can give you a bird’s-eye view of how your queries are performing.

9.   Using Default Error Pages

The Mistake: While Rails’ default error pages are useful in a development environment, they can expose unnecessary information in production and aren’t user-friendly.

How to Avoid: In the real world of production, it’s all about balancing user experience with security. Standard Rails error pages can unintentionally flash some sensitive system info.

Besides, they’re not exactly comforting to users who stumble upon them. Give your application a makeover by designing bespoke error pages. These should be useful, discreet, and reassuring, helping users navigate without causing alarm.

10.  Ignoring Security Best Practices

The Mistake: Rails is like a fortress with many built-in security features. But if you don’t use them properly, you might just leave the gate wide open.

How to Avoid:  Web threats come in all shapes and sizes – from sneaky SQL injections to malicious cross-site scripting. While Rails equips you with tools like SQL parameterization and CSRF tokens to fend off many of these threats, a small slip can make you vulnerable.

Tools like brakeman can be your trusty scouts, pointing out potential security risks. Security should always be a top priority, and regular audits and reviews can help maintain a robust security posture.


Ruby on Rails, while incredibly powerful and developer-friendly, is not without its intricacies. Avoiding the above mistakes will set you on a path toward crafting more efficient, maintainable, and secure Rails applications. Remember, the key to mastering Rails lies not just in understanding its features but also in recognizing and avoiding potential pitfalls.

Kokou Adzo is the editor and author of He is passionate about business and tech, and brings you the latest Startup news and information. He graduated from university of Siena (Italy) and Rennes (France) in Communications and Political Science with a Master's Degree. He manages the editorial operations at

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