Ruby on Rails Interview Question

Ruby on Rail Interview Question - Optymize


This is a comprehensive guide on Ruby on Rails Interview Questions and Answers. It has three sets of important Ruby on Rails interview questions and answers: Beginners, Intermediate and Advanced. 

With the help of our sure-fire Ruby on Rails interview preparation guide, you can ace your upcoming interview and land your dream position as a Ruby on Rails developer.


You will succeed in your interview for a Ruby on Rails programmer if you prepare well for the questions. You must be prepared for the most common queries if you are applying for a job requiring you to work with the Ruby on Rails web application framework.

Many renowned businesses, like Twitter, Airbnb, Hulu, Netflix, GitHub, Bloomberg, and many others, use Ruby extensively. Rails is used to create 90% of Ruby web apps. Class hierarchies, encapsulation, inheritance, and polymorphism are important ideas that you must be prepared for, as are more complex ideas like multithreading and deploying your Rails application.

Check out our technical interview resources, interview questions and e-book to prepare for technical interviews if you’re a software engineer, code engineer, software developer, engineering manager, or tech lead. 

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Ruby on Rails interview questions for Beginners

1. Tell us about the Architecture of Ruby on Rails

The Model-View-Controller (MVC) architecture paradigm is used by Ruby on Rails to make the application more maintainable.

The application’s business logic and the rules for data manipulation are carried by the model layer. The view represents the user interface, the application’s front end. Models and views interact with each other using controllers. The controllers process the incoming requests from the browsers, processing the data from the models before passing it to the views for presentation.

2. What is the function of Active Record in Ruby?

Its key goal is to make sure that all validations may be taken into account on time and that the relationship between the object and the database is preserved.

3. What do you know about the Ruby on Rails ERB?

Users of this web application framework are provided with a programme known as ERB. Actually, it is an acronym for Embedded Ruby. This should be taken into account when directly inserting Ruby-related codes into HTML files. The nicest part about this programme is that even when they are complicated, users don’t need to worry.

4. Mention some of the facts which you find really good about Ruby

Well, Ruby contains everything an ideal web application framework actually needs to have, and the best part is that when compared to Java or any other parallel framework, web apps can be produced much more quickly. The users are free to move forward and maintain the pace easily, even when creating web applications that are supported by databases. The consumers don’t actually need to worry about the necessary compilation process, which is the next positive development. Additionally, users can very easily configure the code with the database.

5. Is it possible in Ruby to develop database-driven applications? What is the basic approach?

The model view controller pattern in Ruby can assist in developing data-driven applications. Additionally, when developing the code, users may simply ensure that it is not overly complicated.

6. What can you tell us about the Ruby on Rails action controller?

This is essentially a crucial aspect of Ruby that ensures that traffic is directed on the one hand and that models can be queried in a trustworthy manner on the other. Additionally, it arranges and defines data in a way that is applicable all over the domain.

Intermediate Ruby on Rails Interview Questions

With some practise, you’ll be able to react fluently to fundamental Ruby on Rails interview questions. In this section, we’ve gathered some difficult Ruby on Rails interview questions for you. This section might help you prepare for the specific types of intermediate Ruby on Rails interview questions you can encounter when looking for work.

1. What do you mean by the term "scaffolding" and what benefits might Ruby provide in this regard?

Users frequently have to write codes in the first stages of project development. These programmes make it possible to swiftly and reliably create the application while also keeping a careful check on the operation of several key parts. Ruby automatically builds the scaffolding, leaving users free to focus solely on the core development from the very first day of creation.

2. What prerequisites must be met before using Ruby on Rails to create a project?

To store and manage all actions and related programmes, a webserver and database system should be installed on the system. Additionally, a trustworthy installation of Ruby and the Rails framework are required. Users can use the WeBrick server that is included with this framework. Generally speaking, Apache and TPD are two other options that most users frequently choose.

3. Name a few Directories in ruby and explain their purpose

App – In essence, it is in charge of organising the application’s parts. Typically, it contains all of the useful subdirectories.
App View – these Views have identical display templates and fill them with information from a separate framework.

3. What does Ruby on Rails' object relationship model actually mean?

The object relationship model clearly shows that all classes are quickly mapped to the systems, and the best part is that users are free to maintain the pace over time. Additionally, it shows how the tables and rows are linked to the classes.

4. What does Ruby on Rails' garbage collection mean?

It only ensures that any pointer values that are left over after a programme has been executed should be erased consistently. Additionally, users can eventually unwind while tracking the objects repeatedly. With this method, all objects that are no longer needed can be removed immediately from the memory.

5. What exactly do you mean by "rail migration"?

It is essentially a method that users may utilise to construct a version control system and make modifications to the Ruby database Schema that is already in place. To produce high-quality results, the fundamental goal is to synchronise the objects.

6. What does rake in Rails mean?

Rake is a Ruby Make; it is a Ruby tool that replaces the Unix tool “make” and creates a list of tasks using a “Rakefile” and “.rake files.” Rake is used in Rails to do routine administrative operations like loading a schema into the database and migrating the database using scripts.

Advanced Ruby on Rails interview questions

This section contains some advanced interview questions for Ruby on Rails jobs. Read and Understand how these complex technologies work and how they help businesses. We have also covered ruby on rails coding interview questions in this section.

1. Explain Interpolation in Ruby

Interpolation is the process of adding a string into a literal. In Ruby, interpolation is a crucial procedure. There is only one method for interpolation: by embedding # inside {}. The copy of the original name is used to refer to a new name.

2. What distinguishes the words "delete" and "destroy"?

The delete function doesn’t execute any callbacks; it just purges the record based on the record’s primary key.

The destroy function run callbacks like before_destroy, after_destroy, and observer methods as well as any dependent records in addition to deleting the record from the database.

3. Explain Ruby on Rails' Polymorphic Association.

Ruby on Rails’ polymorphic association feature enables connections between ActiveRecord objects. The polymorphic association, for instance, makes it feasible to create a social network where members can remark on movies, photographs, links, status updates, and more. You would need to build a unique comment, such as photos comments, status comments, and so forth, without polymorphic association.

4. What Does Rails' Meta-Programming Mean?

Ruby makes meta-programming in Rails more effective. In Rails, the concept of meta-programming allows your application to build functions, methods, or classes while it is running and call them dynamically. Route helpers are an illustration of meta-programming at action in Rails. By using meta-programming, you may query your code about itself while it is running, which makes jobs easier to do than in another language.

4. How Does Active support "HashWithIndifferent" Differ From Ruby's "Hash"?

The Hash class in the core library of Ruby returns value by performing a simple “= =” comparison on the keys. The comparable string cannot be used to get the stored value for a symbol key. The HashWithIndifferent, in contrast, handles the symbol and string keys equally.

5. How Do Ruby on Rails Observers Differ From Callbacks?

Similar to callbacks, rails observers are used when the method isn’t directly related to the object lifecycle. The observer can be connected or detached as needed and has a longer lifespan. For example, you may use it to update models based on user input and display model values in the user interface.

In Rails, callbacks are methods that can be used at specific points in an object’s lifecycle. It can be used to validate, update, create, or delete an item. This won’t last long. You could, for instance, run a thread and respond with a callback when it finishes.

6. What Does Rails Migration Mean? How Can a Rails Migration Be Created?

Ruby can alter the database schema thanks to migration in Rails, and you can utilise a VCS (version control system) to keep everything in sync with the actual code. The following tasks can be performed with Rails migration: Rename table
Drop table
Rename column
Change column
Add column
Create table
Remove column and so on
To build a migration command, use the following Rails code (For windows): C:\ruby\application>ruby script/generate migration table_name.

7. How is Ajax implemented in Rails?

In Rails, submitting an Ajax request is simple. It starts an Ajax operation by doing the following:

When a user hits a button or a link, the data in the field or on a form is changed.

When a web client delivers data to a server-side action handler associated with the trigger using an XMLHttpRequest, a Java-script method, or both (it may be the ID of a checkbox or the text in the entry field).

The server-side action handler processes the data, extracts a piece of HTML, and sends it to the web client.

The HTML fragment is delivered to the client-side JavaScript, which Rails automatically generates, and is then used to update a specific section of the current.

8. How You Run Your Rails Application Without Creating Databases?

You can run your application by uncommenting the line in the environment.rb path=> rootpath conf/environment.rb config.frameworks-=[action_web_service,:action_mailer,:active_record


We are confident that these Ruby on Rails interview questions and answers will be of great assistance to you throughout the process, whether you are a developer preparing for an interview or a hiring manager looking for the best applicant.

Remember that the hiring process involves more than just technical competence. If you want to be hired for a high-paying web development profession, you must have both previous experience and soft skills.

Remember that many of the open-ended Ruby on Rails interview questions. The interviewer will be interested in your rationale in addition to the answer you memorably provided. Be ready to respond to any follow-up questions about how you arrived at your decision. Describe your proper thought process.

Good Luck! Regarding your future Ruby on Rails interview. You can browse through our listings for Ruby on Rails developer jobs here.