100 Must-Know Ruby on Rails Interview Questions and Answers 2024

Ruby on Rails Fundamentals

1.
What is Ruby on Rails, and why is it popular for web development?
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2.
Describe the MVC architecture in Rails.
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3.
What are Gems and how do you use them in a Rails project?
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4.
What is the purpose of the Gemfile in a Rails application?
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5.
How do you install a Ruby gem?
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6.
Explain how to generate a new Rails application.
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7.
What is the convention over configuration principle?
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8.
How do you define a route in Rails?
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9.
Explain the use of yield in Rails layouts.
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10.
What is CRUD, and how is it implemented in Rails?
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Rails Controllers and Actions

11.
What is the purpose of a controller in Rails?
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12.
How do you pass data from a controller to a view?
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13.
Explain the Rails controller action lifecycle.
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14.
How do you handle parameters in a controller action?
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15.
What filters are available in Rails controllers and how do you use them?
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16.
How do you implement redirects in a Rails controller?
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17.
What is a strong parameter, and why should you use it?
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18.
Explain the differences between member routes and collection routes.
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19.
How do you handle session data in Rails?
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20.
What is the flash in Rails, and how do you use it?
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Rails Models and Active Record

21.
What is Active Record, and how does it work?
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22.
How do you create a new Active Record model?
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23.
Explain migrations in Rails and their role.
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24.
What are validations in a Rails model, and why are they important?
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25.
How do you establish associations between Rails models (e.g., has_many, belongs_to)?
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26.
Explain the concept of callbacks in a model.
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27.
How are queries built using Active Record?
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28.
What is the N+1 query problem, and how do you solve it?
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29.
How do you manage database transactions in Rails?
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30.
What is polymorphic association in Rails?
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Rails Views and the Asset Pipeline

31.
How do you use the asset pipeline in Rails?
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32.
What is the role of helpers in Rails views?
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33.
Explain the difference between .erb, .haml, and .slim view templates.
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34.
How do you use partials in Rails?
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35.
What are Rails layouts, and how do you use them?
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36.
How do you implement form validations on the client-side using Rails?
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37.
What is Turbolinks, and how does it affect Rails applications?
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38.
Explain how Webpacker is used with Rails.
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39.
How do you include JavaScript or CSS files in Rails assets?
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40.
What are data-* attributes and how do you use them in Rails views?
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Rails Testing

41.
What is Test-Driven Development (TDD) and how is it applied in Rails?
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42.
Explain the differences between unit, functional, and integration tests in Rails.
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43.
How is RSpec used in Rails testing?
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44.
What is Capybara, and what role does it play in testing?
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45.
How do you create fixtures and factories for test data in Rails?
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46.
What is a test runner, and which ones are commonly used in Rails?
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47.
How do you run a specific test file or test case in Rails?
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48.
Describe the purpose of Mocks and Stubs in testing.
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49.
How do you test a Rails API?
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50.
What are system tests and how do you implement them in Rails?
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Rails Security

51.
How does Rails handle CSRF (Cross-Site Request Forgery) protection?
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52.
What are some common security vulnerabilities in web applications, and how does Rails address them?
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53.
How do you implement user authentication in a Rails application?
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54.
Explain the use of the Devise gem for authentication.
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55.
What are Rails security headers, and how are they set?
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56.
Explain SQL injection and how Rails prevents it.
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57.
How do you store sensitive data securely in Rails?
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58.
What is the Rails encrypted credentials feature?
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59.
How does Rails handle password hashing?
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60.
What is the purpose of the has_secure_token method in Rails?
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Rails Performance

61.
Describe some ways of optimizing the performance of a Rails application.
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62.
How do you identify performance bottlenecks in a Rails app?
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63.
What is caching in Rails, and what are the different types of caching strategies?
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64.
How do you use Background Jobs in Rails?
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65.
What is the purpose of Eager Loading, and how is it used?
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66.
How do you use the Bullet gem to identify N+1 problems?
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67.
What are some tools you can use for performance monitoring in Rails?
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68.
What are HTTP/2 Server Push and how can you use it in Rails?
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69.
How do you perform database indexing in Rails, and why is it important?
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70.
How does connection pooling work in Rails?
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Rails Best Practices and Design Patterns

71.
What is the DRY (Don’t Repeat Yourself) principle, and how do you follow it in Rails?
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72.
Explain the fat-model, skinny-controller approach in Rails.
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73.
What are service objects, and when should they be used?
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74.
How do you implement a decorator pattern in Rails?
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75.
What are some common Rails anti-patterns?
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76.
Describe the role of a presenter in the Rails architecture.
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77.
How do you modularize a large Rails application?
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78.
Describe the Single Table Inheritance and Polymorphic Association design patterns in Rails.
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79.
What are concerns in Rails, and how do you use them?
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80.
How do you keep a Rails codebase clean and maintainable over time?
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Advanced Rails Features

81.
Explain the Rails internationalization API (I18n).
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82.
How do you implement real-time features in Rails (e.g., ActionCable)?
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83.
What is the role of Active Job in Rails?
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84.
Explain how multi-tenancy works in Rails.
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85.
How do you generate PDFs in Rails?
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86.
How do you implement file uploading in Rails?
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87.
What is Rack, and how does Rails interact with it?
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88.
How do you monitor a Rails application in production?
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89.
How do you create APIs in Rails (using Rails API mode)?
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90.
Explain how to use Rails Engines to modularize an application.
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Rails Ecosystem and Community

91.
What are some popular Gems that most Rails applications will use?
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92.
How can you contribute to the Rails community?
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93.
What is the latest version of Rails, and what are its new features?
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94.
How do you stay up-to-date with Rails developments?
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95.
What are some resources for learning best practices in Rails?
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96.
Describe the Rails release cycle and versioning system.
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97.
How does the Ruby version affect a Rails application?
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98.
What are some alternatives to Rails for Ruby web development?
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99.
How do you deploy a Rails application to a production environment?
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100.
How does Rails integrate with modern frontend frameworks like React or Vue.js?
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100 Ruby on Rails interview questions

What is Ruby on Rails, and why is it popular for web development?

Describe the MVC architecture in Rails.

What are Gems and how do you use them in a Rails project?

What is the purpose of the Gemfile in a Rails application?

How do you install a Ruby gem?

Explain how to generate a new Rails application.

What is the convention over configuration principle?

How do you define a route in Rails?

Explain the use of yield in Rails layouts.

What is CRUD, and how is it implemented in Rails?

What is the purpose of a controller in Rails?

How do you pass data from a controller to a view?

Explain the Rails controller action lifecycle.

How do you handle parameters in a controller action?

What filters are available in Rails controllers and how do you use them?

How do you implement redirects in a Rails controller?

What is a strong parameter, and why should you use it?

Explain the differences between member routes and collection routes.

How do you handle session data in Rails?

What is the flash in Rails, and how do you use it?

What is Active Record, and how does it work?

How do you create a new Active Record model?

Explain migrations in Rails and their role.

What are validations in a Rails model, and why are they important?

How do you establish associations between Rails models (e.g., has_many, belongs_to)?

Explain the concept of callbacks in a model.

How are queries built using Active Record?

What is the N+1 query problem, and how do you solve it?

How do you manage database transactions in Rails?

What is polymorphic association in Rails?

How do you use the asset pipeline in Rails?

What is the role of helpers in Rails views?

Explain the difference between .erb, .haml, and .slim view templates.

How do you use partials in Rails?

What are Rails layouts, and how do you use them?

How do you implement form validations on the client-side using Rails?

What is Turbolinks, and how does it affect Rails applications?

Explain how Webpacker is used with Rails.

How do you include JavaScript or CSS files in Rails assets?

What are data-* attributes and how do you use them in Rails views?

What is Test-Driven Development (TDD) and how is it applied in Rails?

Explain the differences between unit, functional, and integration tests in Rails.

How is RSpec used in Rails testing?

What is Capybara, and what role does it play in testing?

How do you create fixtures and factories for test data in Rails?

What is a test runner, and which ones are commonly used in Rails?

How do you run a specific test file or test case in Rails?

Describe the purpose of Mocks and Stubs in testing.

How do you test a Rails API?

What are system tests and how do you implement them in Rails?

How does Rails handle CSRF (Cross-Site Request Forgery) protection?

What are some common security vulnerabilities in web applications, and how does Rails address them?

How do you implement user authentication in a Rails application?

Explain the use of the Devise gem for authentication.

What are Rails security headers, and how are they set?

Explain SQL injection and how Rails prevents it.

How do you store sensitive data securely in Rails?

What is the Rails encrypted credentials feature?

How does Rails handle password hashing?

What is the purpose of the has_secure_token method in Rails?

Describe some ways of optimizing the performance of a Rails application.

How do you identify performance bottlenecks in a Rails app?

What is caching in Rails, and what are the different types of caching strategies?

How do you use Background Jobs in Rails?

What is the purpose of Eager Loading, and how is it used?

How do you use the Bullet gem to identify N+1 problems?

What are some tools you can use for performance monitoring in Rails?

What are HTTP/2 Server Push and how can you use it in Rails?

How do you perform database indexing in Rails, and why is it important?

How does connection pooling work in Rails?

What is the DRY (Don’t Repeat Yourself) principle, and how do you follow it in Rails?

Explain the fat-model, skinny-controller approach in Rails.

What are service objects, and when should they be used?

How do you implement a decorator pattern in Rails?

What are some common Rails anti-patterns?

Describe the role of a presenter in the Rails architecture.

How do you modularize a large Rails application?

What are data- attributes* and how do you use them in Rails views?