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Top 45 Scala Interview Questions & Answers (2026)

45 Questions 20 Beginner 15 Intermediate 10 Advanced

About Scala

This technology is widely used in software development and is a frequent topic in technical interviews at companies of all sizes.

What to Expect in a Scala Interview

Interviews cover both foundational concepts and practical application of this technology, with questions ranging from definitions to architectural decision-making.

How to Use This Guide

Work through questions in order of difficulty to build your understanding progressively. Bookmark challenging questions and revisit them before your interview.

Curated by Tech Baithak Editorial Team · Last updated: May 2026

Beginner 20 questions

Core concepts every Scala developer must know.

01 What is Scala and what are its key features? 02 What is the difference between val and var in Scala? 03 What are case classes in Scala? 04 What is pattern matching in Scala? 05 What is Option in Scala and how does it replace null? 06 What is the difference between List and Array in Scala? 07 What are higher-order functions in Scala? 08 What are traits in Scala? 09 What is implicit in Scala? 10 What is the for-comprehension in Scala? 11 What is lazy evaluation in Scala? 12 What is Scala's type system and what is type inference? 13 What is the companion object in Scala? 14 What are sealed traits and classes in Scala? 15 What is the difference between def, val, and lazy val for methods/values? 16 What is the Either type in Scala? 17 What is tail recursion in Scala? 18 What is the difference between == and eq in Scala? 19 What is a Future in Scala? 20 What is Scala's collections library and its main categories?

Intermediate 15 questions

Practical knowledge for developers with hands-on experience.

01 What is the type class pattern in Scala? 02 What is Akka and what is the actor model? 03 What is Apache Spark and how does Scala relate to it? 04 What is Scala's approach to concurrency with Futures and Promises? 05 What are Scala's monads and how do they work? 06 What is Cats library in Scala? 07 What is Scala 3 (Dotty) and its major changes? 08 What is Play Framework in Scala? 09 What is Slick in Scala? 10 What are type bounds in Scala generics? 11 What is variance in Scala generics? 12 How does error handling work with Try in Scala? 13 What is the difference between abstract class and trait in Scala? 14 What is the cake pattern in Scala? 15 What are Scala macros and when are they used?

Advanced 10 questions

Deep expertise questions for senior and lead roles.

01 What is ZIO and how does it compare to Cats Effect? 02 What is FS2 (Functional Streams for Scala)? 03 What is Shapeless in Scala? 04 What is the Scala STM (Software Transactional Memory) model? 05 How does Scala's type system handle path-dependent types? 06 What is the Scala concurrency model compared to Java? 07 What are higher-kinded types in Scala and why are they important? 08 What is opaque type alias in Scala 3? 09 How does Scala's pattern matching relate to algebraic data types (ADTs)? 10 What are Scala's inline and transparent inline features in Scala 3?

Back to All Topics 45 questions total