Rails Interview Questions for Developers

Use our engineer-created questions to interview and hire the most qualified Rails developers for your organization.

Rails is a Ruby-based back-end framework known for its emphasis on promoting code reusability (the Don’t Repeat Yourself principle), vast Rapid Application Development tool library, and Model-View-Controller (MVC) pattern support.

Rails follows the software design principle “convention over configuration,” which means that it provides a set of conventions and sensible defaults to minimize the amount of configuration developers need to do. This approach helps reduce boilerplate code, speeds up development, and promotes best practices.

https://rubyonrails.org/doctrine/

In order to assess the proficiency of developers in Rails during programming interviews, we provide a collection of practical coding tasks and interview queries. Moreover, we’ve devised a series of recommended approaches to guarantee that your interview questions effectively gauge the candidates’ Rails abilities.

Rails example question

Create a Rails CRUD API

The goal of this exercise is to retrieve data from an external source, store it in an appropriate database structure, and create a CRUD RESTful API to interface with the database

Goals

1. Read the data from this graphql endpoint: https://swapi-graphql.netlify.app/.netlify/functions/index with the following query:

query Query {allPlanets{planets{name population terrains climates}}}

(View the shape of the data here.)

2. Store the data from the graphql endpoint into the database and create appropriate models

3. Write RESTful Create, Read, Update, and Delete endpoints to interact with the database

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Interview best practices for Rails roles

To conduct effective Rails interviews, it’s essential to consider various factors, such as the candidate’s experience level and the specific engineering role. To ensure your Rails interview questions yield the best results, we recommend following these best practices when interacting with candidates:

  • Create technical questions that reflect real-world business situations within your organization. This not only makes the interview more engaging for the candidate but also allows you to better assess their suitability for your team.
  • Encourage candidates to ask questions throughout the interview and foster a collaborative environment.
  • If Rails is used as part of a full stack, make sure your developers also possess knowledge of front-end technologies like HTML/CSS and database expertise, particularly with Active Record, which is Rails’ ORM (object-relational mapper) module.

Additionally, it’s important to adhere to standard interview practices when conducting Rails interviews. This includes adjusting question difficulty based on the candidate’s development skill level, providing timely feedback about their application status, and allowing candidates to ask about the evaluation or collaborate with you and your team.