Top 30 Ruby On Rails Interview Questions And Answers

October 5th, 2023
Ruby On Rails Interview Questions

Ruby on Rails is one of the most widely used programming languages in the world. It has an abundance of useful features that help in the faster launching of web applications. A lot of new and experienced programmers like to learn this language because it has a good future ahead. Right preparation along with Ruby on Rails interview questions can definitely help you stand out you from other.

Ruby is being used by some of the top companies in the world for projects that require large transformation, or those that need a lot of complex functions, or that have heavy traffic. Thus, it is being used at a lot of places for a lot of different tasks.

Here are top 30 Ruby on Rails interview questions and answers to help you ace your interview. We have a list of interview questions for entry/junior level, mid-level, and seniors. Thus, no matter where you think you are on the expertise level, this blog has you covered.

Ruby on Rails Tutorial

This Ruby on Rails tutorial will not tell you what ROR is. In fact, this tutorial is for those who begin their success journey in the tech world with this incredible programming language. We have curated a list of some of the most often asked interview questions through all levels of the candidate's experience.

Top 30 Ruby On Rails Interview Questions And Answers

Junior/Entry-Level Ruby on Rails Interview Questions

Here are a few Rails and Ruby interview questions that you might be asked when going for an entry-level position. As a junior, it is difficult to exactly pin which Ruby and Rails interview questions can be put forth by the hiring manager since you only have textual knowledge. But we have composed a list of ten important questions.

Q1. What is Ruby on Rails?

Answer. Ruby is an object-oriented programming language that has taken inspiration from Ada, Lisp, PERL, Basic, Eiffel, and Smalltalk. Rails is a framework that is used to build web applications.  

Q2. What is ORM in Rails?

Answer. ORM stands for Object-Relational-Mapping. Here Classes are mapped to tables in the DB whereas Objects are mapped to the rows in the table.

Q3. How is Ruby on Rails limited?

Answer. Ruby on Rails often finds itself being cited as slow, especially when compared to Golang or NodeJS' runtime speed.

Q4. What is Nil in Ruby?

Answer. Nil is a unique value that depicts the lack of any value. In Ruby, void or nothing is known as nil.

Q5. Explain Rails Migration.

Answer. Rails Migration allows Ruby to alter database schema. This enables using a version control system to synchronize things with the actual code.

Q6. What is rake in Rails?

Answer. Rake is a widely used software task management tool used to group tasks, specify tasks, and describe dependencies in a namespace.

Q7. What are the components of Rails?

Answer. Rails has three main components namely model, view, and controller.

Q8. What are the two guiding principles of the Rails framework?

Answer. The Rails framework is based on two guiding principles.

  • Don't Repeat Yourself (DRY)
  • Convention over Configuration (CoC)

Q9. What are the access modifiers in Ruby?

Answer. There are three access modifiers in Ruby namely Public, Private, and Protected.

Q10. What do you understand about Rails Active Record in ROR?

Answer. Rails active record is the ORM layer supplied with Rails.

Intermediate Level Ruby on Rails Interview Questions

Interviews will ask questions that are one step ahead when you go for an intermediate-level interview. Here are some mid level Ruby programming questions for you.

Q11. Briefly explain the role of sub-directory app/helpers and app/controllers.

Answer. App/helpers - It refers to the helper's sub-directory that holds all helper classes involved in assisting the MVC classes.

App/controllers - The controller handles any web requests from the user. This subdirectory is where Rails get controller classes.

Q12. How is delete different from destroy in Ruby on Rails?

Answer. Delete is used to delete a record. Destroy, on the other hand, is used to both delete a record as well as execute callbacks on the model.

Q13. What does load and require do in Ruby?

Answer. Load is used to execute code whereas require is used to import libraries.

Q14. What are gems in Ruby on Rails?

Answer. Gems in Ruby on Rails refers to a package manager for this programming language. It offers a standard format to help distribute Ruby libraries and programs. It facilitates the developers in implementing various features without the need to code from scratch.

Q15. Explain scaffolding in relation to ROR.

Answer. Scaffolding is an extremely useful feature that creates a basic structure of the application including controllers, routes, views, and models. It speeds up the development process by encouraging best practices and providing a consistent structure.

People also read- Ruby on Rails (ROR)- Benefits, Career Prospects, and Salaries

Q16. How does Scaffolding help developers?

Answer. Scaffolding has a lot of benefits for the developers -

  • Enable fast success 
  • It can be used to jumpstart all developments
  • The code can easily and quickly be presented to the user for feedback

Q17. What are helpers and how are they used in ROR?

Answer. Helpers are modules offering automatically usable methods in the view. These modules offer shortcuts to many commonly used display codes. The aim is to simplify the view.

Q18. How can you define Global Variable, Class Variable, and Instance Variable in Ruby?

Answer. - Instance Variable begins with @.

  • Class Variable begins with @@
  • Global Variable begins with $

Q19. What are the positive points of Rails?

Answer. Rails have a lot of positive points including-

  • Meta-programming: Rails relies on meta-programming for heavy lifting even though it uses code generation. It is counted among one of the top languages for meta-programming.
  • Scaffolding: Rails has the feature of creating temporary code automatically.
  • Three Environments: Testing, development, and production are the three default environments Rails comes with.
  • Active Record: The Rails version points out the column in a schema. Meta-programming is used to automatically bind them to the domain objects.
  • Build-in Testing: Rails has two codes titled harness and fixtures.

Q20. How is a gem different from a plugin in Ruby?

Answer. Both gem and plugin are Ruby codes. However, gem is installed on a machine whereas a plugin is installed in the app folder. The former is available for all Ruby apps on the machine. The latter is available for that particular application.

Senior Level Ruby on Rails Interview Questions

Here is a list of a few senior level Ruby coding interview questions and answers. We hope a list of interview questions Ruby on Rails will help you crack an interview with your dream company. Let's begin! 

Q21. What do you understand about Strong Params in Rails?

Answer. A lot of Rails apps utilize Strong Params or Strong Parameters that help in strengthening the security of the data that is supplied via forms. This feature facilitates developers in deciding which parameters are accepted and then used in the controller.

Only the expected params are allowed and any potentially hazardous or superfluous params are filtered out. This feature comes in handy when the developer is using Active Model bulk assignments.

Q22. How is Rails Observers different from Rails Callback?

Answer. Rails callback is a method that can be called at certain specific moments throughout the life cycle of an object. These moments include events like creation, deletion, updation, or validation of an object.

Rails Observers, while quite similar to Callback, are employed when the method is not in direct association with the object lifecycle. These tend to live longer and can be attached or detached as per the requirement.

Q23. What is the purpose of garbage collection in ROR?

Answer. Garbage collection has an integral role to play in ROR.

  • It facilitates the removal of the leftover pointer values during the end of the execution of the program.
  • It removes inaccessible objects from the memory that in turn makes space for other processes.
  • It gives the programmer freedom from tracking the object that is dynamically being created on runtime. 

Q24. How is Redirect different from Render in Ruby on Rails?

Answer. Both Redirect and Render are methods. The former is used for issuing the error message if the page is not found or not issued to the browser. It sends a message to the browser to process the case and issue a new request. The latter is used for making the content. This method works best when the controller and the variables are set  up properly.

Q25. Briefly talk about the types of association models in Ruby on Rails.

Answer. Associations are used to create a connection between different models in an application. The three main types of associations are -

  • One-to-one: where one object is linked to a single other object
  • One-to-many: where one object has to scope to be related to various other objects
  • Many-to-many: where many one type of objects can be linked to many second types of objects. 

Q26. How is Ruby on Rails different from Python?

Answer. There are quite a lot of aspects on which Ruby on Rails differs from Python. Here they are -

  • Popularity: Python is higher on the popularity list as compared to Ruby. more new programmers are inclined towards Python. 
  • Community: Python has a bigger community. 
  • Web Frameworks: Python is a programming language while ROR is a web development framework. 
  • Learning Curve: Ruby is a bit more complex to learn than Python. 
  • Usage: ROR has a more focused approach towards functional web application development. Python, on the other hand, is more inclined towards apps in the academic research or scientific domain. 
  • Applications: Ruby is a better fit for applications intended to support heavy traffic. 
  • Inheritance: Ruby supports single inheritance but Python can support multiple inheritance. 

Q27. Can Ruby be called a flexible language?

Answer. Yes, Ruby is a highly flexible language as the user can easily and freely alter its parts as per their convenience. Ruby has done a good job at ensuring it does not restrict the coder. Any essential Ruby's part can be redefined or even removed as per the user's will.

Q28. What are some of the key features of Ruby?

Answer. Some key features of Ruby are -

  • Object Oriented: Every value in Ruby is an object, which further has a class, which further has a super-class. 
  • Flexible: The coder can easily add, remove, or redefine the existing parts. 
  • Dynamic Typing: Ruby programs are not compiled. Rather, all method, module, and class definitions are built by the coder when it is run. 
  • Case Sensitive: There is a clear distinction between uppercase and lowercase letters. 
  • Statement Delimiters: A semicolon is used to separate multiple statements in a single line. However, using it at the end of the line is not necessary.

ruby interview questions

Q29. What is a Class Library in Ruby?

Answer. A class library in Ruby is composed of a lot of domains including various domains, data types, thread programming, etc. these classes offer flexible capabilities at an upper level of abstraction, rendering the coders with the power to create impactful scripts that can be used in different problem domains. Domains with relevant class libraries include -

  • Network programming
  • Text processing
  • GUI programming
  • CGI programming

Q30. How is String different from text in Rails?

Answer. Text and string fields both hold information that can be freely written in. The major difference between String and Text lies in how many characters can be put in each.

The character limit of a string field is 255. Thus, it is best suited for storing data like name, address, etc.

The character limit of a text field is 30,000. Thus, it is best suited for storing data such as a comment box on a form.

Why Learn Ruby on Rails Today?

Ruby on Rails is a leading programming language. However, there are many others that are even above it. So, why should you learn Ruby on Rails rather than going for it competitive languages like Python or JavaScript? Here is why this language is the best for you-

  • It is a versatile language that helps programmers achieve way more with way less code.
  • The market for Ruby Developers is expanding. Ruby developers are high in demand and as years ago, this demand is going to increase.
  • Ruby Developers enjoy lucrative salaries as the demand is higher. Thus, a good and experienced Ruby developer is sure to enjoy monetary benefits.


When you set your mind on becoming a Ruby on Rails developer, it is important to get trained from the right place and for that you can consider online Ruby on Rails training and course. Cracking the interview is one of the key steps of getting a job. This blog will help you find an answer to some of the most commonly asked questions in an interview.

Ruby On Rails Interview Question FAQs (Frequently Asked Questions)

Q1. What soft skills should I have as a Ruby on Rails expert?

Ans. Some of the most important soft skills to have include effective communication, problem solving, attention to detail, critical thinking, and time management.

Q2. Is Ruby better than Python?

Ans. Ruby is a good fit for commercial web applications whereas Python is a better fit for people who want to quickly develop websites.

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