Scala Interview Questions for Developers

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

Developed to address the weaknesses of Java, Scala maintains compatibility with the Java Virtual Machine (JVM) while having more concise syntax, embracing functional programming (in addition to object-oriented programming), and having more powerful type inference.

Drawing inspiration from multiple programming languages such as Java, Haskell, and ML, Scala combines the object-oriented and functional programming paradigms in an effort to offer the most advantageous aspects of each.

We have developed practical coding assignments and interview questions tailored to evaluate developers’ Scala skills during coding interviews. Furthermore, we have compiled a set of best practices to ensure that your interview questions accurately gauge the candidates’ proficiency in Scala.

Scala 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

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Best interview practices for Scala roles

To conduct successful Scala interviews, it’s essential to consider various factors, including the candidate’s background and the specific engineering role. To ensure a fruitful interview experience, we recommend adopting the following best practices:

  • Develop technical questions that reflect real-world business scenarios within your organization. This approach will effectively engage the candidate and assist in evaluating their compatibility with your team.
  • Cultivate a cooperative environment by encouraging candidates to ask questions throughout the interview.
  • You’ll also want to ensure your candidates have an understanding of concurrent and parallel programming.
  • Scala is very often used with Spark (a large-scale data processing engine). If needed, try to evaluate your candidates’ knowledge concerning this tool, beside their generic Scala knowledge.

Moreover, adhering to established interview procedures is critical when conducting Scala interviews. This encompasses adjusting the complexity of the questions to match the candidates’ skills, promptly informing them about the status of their application, and providing them with the opportunity to ask about the evaluation process and collaboration with you and your team.