Ruby Interview Questions for Developers

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

Ruby demands a respectable following due to its super-clean syntax, large open-source library of RubyGems, and because it forms the basis of the extremely popular Ruby-on-Rails front-end framework.

Ruby is unique for its Principle of Least Astonishment (POLA), which dictates that the language’s behavior should minimize surprises for its users to make it a more intuitive language to learn and use.

We have crafted practical coding exercises and interview questions designed to assess developers’ Ruby expertise during coding interviews. Additionally, we have put together a collection of best practices to guarantee that your interview questions effectively measure the candidates’ proficiency in Ruby.

Ruby example question

Help us design a parking lot

Hey candidate! Welcome to your interview. Boilerplate is provided. Feel free to change the code as you see fit. To run the code at any time, please hit the run button located in the top left corner.

Goals: Design a parking lot using object-oriented principles

Here are a few methods that you should be able to run:

  • Tell us how many spots are remaining
  • Tell us how many total spots are in the parking lot
  • Tell us when the parking lot is full
  • Tell us when the parking lot is empty
  • Tell us when certain spots are full e.g. when all motorcycle spots are taken
  • Tell us how many spots vans are taking up


  • The parking lot can hold motorcycles, cars and vans
  • The parking lot has motorcycle spots, car spots and large spots
  • A motorcycle can park in any spot
  • A car can park in a single compact spot, or a regular spot
  • A van can park, but it will take up 3 regular spots
  • These are just a few assumptions. Feel free to ask your interviewer about more assumptions as needed

1,000 Companies use CoderPad to Screen and Interview Developers

Best interview practices for Ruby roles

In order to conduct successful Ruby interviews, it is essential to take into account various factors, such as the candidate’s background and the specific engineering role. To guarantee a productive interview experience, we suggest implementing the following best practices:

  • Formulate technical questions that represent real-world business situations within your organization. This method will effectively engage the candidate and help assess their fit with your team.
  • Foster a collaborative atmosphere by encouraging the candidate to ask questions during the interview.
  • If you’re employing Ruby in a full-stack capacity, ensure that the candidate possess a fundamental understanding of HTML & CSS.

Furthermore, adhering to established interview procedures is crucial when conducting Ruby interviews. This includes adjusting the difficulty of the questions to align with the candidate’s abilities, promptly updating them on the status of their application, and offering them the chance to inquire about the evaluation process and collaborating with you and your team.