Duolingo Software Engineer Interview Questions
& Process
Real candidates share what happened, how many rounds they had,
and how the experience turned out.
Based on 122 interview experiences · FREE TO READ
Candidate interview experiences
First-hand accounts from people who interviewed at Duolingo.
Duolingo
Software Engineer
Entry Average Neutral experience Decline offer 3 rounds
Interview process
Technical screen Technical screen Technical screen
Interview formats
Coding Coding Coding
The interview process included an onsite interview with three parts: first, a code review round on codesignal where I had to review a pull request and comment on code quality and errors. Second, a whiteboard session to solve a LeetCode Medium problem. Lastly, a pair programming session with a Senior Engineer on a toy demo using VS Code Codesharing.
Confirmed questions2 questions
- Did you prepare questions to ask about the job responsibilities?
- Can you tell me about the job responsibilities?
Duolingo
Software Engineer
Senior Easy Positive experience Decline offer 4 rounds
Interview process
Recruiter call Technical screen Onsite Background check Offer
Interview formats
Behavioral Coding Technical System Design Presentation
It started with a situational interview with a team member and a pair programming exercise. Then, if I passed that, the onsite consisted of a deep dive into an engineering project I'd worked on, an interview reviewing an infrastructure as code pull request, and finally a culture fit interview. After that, it was background check and offer.
Confirmed questions2 questions
- Could you fix a bug in a provided buggy implementation of an app feature, and then enhance its functionality through increasing levels of complexity?
- Given a buggy implementation of a feature in the app, fix the bug and then improve the feature functionality through increasing levels.
Duolingo
Software Engineer Intern
Intern Easy Neutral experience Accept offer 4 rounds
Interview process
Take home Recruiter call Phone screen Technical screen Background check
Interview formats
Coding Behavioral Technical
The interview process included an easy, unproctored code signal test. This was followed by a brief 15-minute behavioral interview where I was asked up to four questions about my past experiences. Neither the technical nor the behavioral interview required prior software experience.
Confirmed questions3 questions
- I was asked a question about a matrix.
- There was also a question about strings.
- And a question concerning arrays, though a perfect score wasn't expected on this one.
Duolingo Software Engineer Interview Questions
Quoted word for word from Duolingo interview reports.
“Could you encrypt and decrypt a string using only lowercase English letters based on a provided dictionary?”
Read reports →“Could you implement a snake game, following specific rules? The game class should have an __init__ method accepting the map size and initial snake positions (body and head). It also needs a move function for directional changes (left, right, up, down). Importantly, the snake must avoid self-collision and stay within the map's boundaries.”
Read reports →“Create a friendship graph from given data and identify all individuals who fulfill a complicated requirement.”
Read reports →“Solve the problem of finding the smallest subarray that meets a specific criterion.”
Read reports →“Can you implement a function that, given a list of valid words, maps a phone number to the words it might spell?”
Read report →“What is the runtime of these two algorithms, and which one is faster? Under what circumstances might one algorithm perform better than the other?”
Read report →“Given multiple functions that achieve the same outcome, analyze their runtime and space complexity.”
Read report →“Could a data structure with a given trace of add and pop operations be a stack, priority queue, or queue?”
Read report →“How would you merge two lists or maps in the most efficient way possible?”
Read report →Formats, difficulty and experience
Across all 122 Duolingo interview reports.