Type · Algorithmic
Design a data structure that supports efficiently adding user comments, retrieving comments for a specific post, and retrieving a user's most recent comments. Discuss time and space complexity.
How to Pass the Reddit Software Engineer Interview in 2026
The Reddit Software Engineer interview runs 5 rounds: Recruiter Screen, Coding Screen, System Design, Onsite Coding, and Behavioral / Leadership. Reddit takes applications through Greenhouse. JobMentis holds 14 Software Engineer questions for Reddit, last updated November 10, 2026.
Growth · Software Engineer Interview Guide
Applies via GreenhouseHeadquartered in United StatesInterview language: English
The Reddit DNA (TL;DR)
Reddit assesses product sense and technical depth, evaluating how candidates build for communities and scale features like r/popular. Expect system design and behavioral questions grounded in Reddit's unique culture.
The Reddit Interview Loop
Your onsite loop will typically consist of 5 rounds.
- 1
Round 1
Recruiter ScreenMotivation, role fit, logistics. - 2
Round 2
Coding ScreenLeetCode-medium algorithmic problems under time pressure. - 3
Round 3
System DesignDistributed systems, trade-offs at scale, architecture under constraints. - 4
Round 4
Onsite CodingLeetCode-hard problems, reasoning about defects, code clarity, edge cases. - 5
Round 5
Behavioral / LeadershipPast evidence of ownership, influence, resolving conflict.
The Danger Zone: Top Reasons Candidates Fail
Based on our database of Reddit interview outcomes, avoid these common traps:
- Inefficient state synchronization between nodes.
- Inefficient sorting or counting of words.
- Treating live comments like standard posts without optimization.
- Poorly chosen indexing strategies.
Test Yourself: Reddit Interview Questions
Three questions from the Reddit bank.
Type · Behavioral
STARReddit often balances community moderation needs against platform-wide growth objectives. Tell me about a time you had to balance competing technical requirements where one path favored user experience and the other favored system stability or scalability.
Type · Debugging
Root Cause Analysis (Issue Tree + 5 Whys)A critical service responsible for rendering user feeds is experiencing intermittent high latency. Here's a simplified version of the code. Identify potential bottlenecks and suggest fixes.
+ many more questions, signals, and worked examples
Sign up to unlock the full Reddit grading rubric
Reddit Interview Question Bank
A sample from our database, grouped by round. Sign up to see the full set.
9 of 14 questions shown
1
Recruiter Screen
1- 1
Type · Motivation
Why are you interested in working at Reddit, specifically within our SaaS offerings?
2
Coding Screen
3- 2
Type · Algorithmic
Given a stream of user posts, design an algorithm to detect and flag potentially duplicate or near-duplicate content in real-time. Consider efficiency and memory constraints. - 3
Type · Algorithmic
Implement a function to find the k most frequent words in a large corpus of Reddit comments. Assume the corpus is too large to fit into memory. - + 1 more questions in this round (sign up to unlock)
3
System Design
4- 4
Type · System Design
Design a system to recommend relevant subreddits to new users based on their initial interactions and profile information. - 5
Type · System Design
Design a real-time notification system for Reddit. Users should receive notifications for new replies, mentions, and upvotes on their posts. Consider delivery guarantees and latency. - + 2 more questions in this round (sign up to unlock)
4
Onsite Coding
3- 6
Type · Coding
Given a list of user interactions (e.g., upvote, downvote, comment, post) with timestamps, write a function to reconstruct a user's likely browsing session. Define what constitutes a 'session' and handle edge cases. - 7
Type · Coding
You are given a large, unsorted array of post IDs. Implement a function to find if a specific post ID exists within the array, optimizing for the case where the array might be partially sorted or have clusters of similar IDs. Discuss trade-offs. - + 1 more questions in this round (sign up to unlock)
5
Behavioral / Leadership
3- 8
Type · Behavioral
STARTell me about a time you had to make a significant technical decision with incomplete information. How did you approach it, and what was the outcome? - 9
Type · Behavioral
STARDescribe a challenging bug you encountered in a complex system like Reddit's. What steps did you take to diagnose and resolve it, and what did you learn from the experience? - + 1 more questions in this round (sign up to unlock)
Unlock all 14 Reddit questions, free
No credit card. Every question with its framework, the grading signals interviewers score against, and a worked answer for each.
Interview tracks at Reddit
How Reddit's DNA translates across functions. Pick your role.
Reddit resume and cover letter
Reddit takes applications through Greenhouse, so Greenhouse parses your resume before a recruiter reads it. Keep the layout plain and describe your skills in the words of the posting. The interviews usually run in English, so send your resume and cover letter in English unless the posting asks for another language. Give each point in the Reddit DNA above a bullet that proves it.
Check your resume against the Reddit job posting
Upload your resume with the Reddit job description to see your ATS score, the keywords you are missing and what to fix before you apply.
Open
Write your Reddit cover letter
Drafted from your resume and the Reddit posting, so it names what you actually did. You edit it before you send it.
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How Greenhouse handles your application
What Greenhouse does with your resume when you apply to Reddit, and how to format it.
Open
Compare Reddit with similar employers
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Practice Reddit interviews end-to-end
Reddit Mock Interview
Run a live mock interview with our AI interviewer using Reddit-style prompts. Get scored on structure, signal, and answer length - exactly how the real loop grades you.
Open
STAR Stories for Reddit Behavioral Rounds
Build a Story Bank of your past wins, mapped to the leadership signals Reddit interviewers grade on. Reuse them across every behavioral round.
Open
Reddit Interview Prep Hub
The frameworks behind every Reddit round: CIRCLES for product sense, hypothesis-driven debugging for analytical, STAR for behavioral. Learn each one in 10 minutes.
Open
Interview Frameworks
CIRCLES, STAR, AARRR, RICE, MECE. The exact frameworks that make Reddit interviewers nod instead of frown. Step-by-step playbooks with the moves and the pitfalls.
Open
Sample answers
What a strong answer to these Reddit interview questions shows.
Design a data structure that supports efficiently adding user comments, retrieving comments for a specific post, and retrieving a user's most recent comments. Discuss time and space complexity.
A strong answer shows: Combination of hash maps and linked lists/trees.; Understanding of indexing and caching strategies.; Analysis of trade-offs for different data structures..
Reddit often balances community moderation needs against platform-wide growth objectives. Tell me about a time you had to balance competing technical requirements where one path favored user experience and the other favored system stability or scalability.
A strong answer shows: Ability to balance competing engineering priorities; Understanding of platform-level trade-offs; Data-driven decision making; Alignment with community-centric product values.
Frequently asked questions
How many interview rounds does Reddit run for Software Engineer candidates?
5 rounds, in this order: Recruiter Screen, Coding Screen, System Design, Onsite Coding, and Behavioral / Leadership.
What does Reddit look for in Software Engineer candidates?
Reddit assesses product sense and technical depth, evaluating how candidates build for communities and scale features like r/popular. Expect system design and behavioral questions grounded in Reddit's unique culture.
Which applicant tracking system does Reddit use?
Reddit takes applications through Greenhouse.
In which language does Reddit run its interviews?
Reddit usually interviews in English.
How many Reddit Software Engineer interview questions does JobMentis hold?
14 questions across the rounds of the Reddit loop, last updated November 10, 2026.
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