Reddit Interview

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Reddit Interview Process: Complete 2026 Guide

Interviewed at Reddit in early 2024 for a backend engineer role. The process was surprisingly rigorous for a company of their size. Here’s everything you need to know.

Overview

Reddit is at an interesting phase – post-IPO, scaling rapidly, but still maintaining that startup-ish culture. The interview reflects this: expect FAANG-level technical rigor but with more emphasis on practical engineering and less on obscure algorithms.

They care a lot about handling scale – Reddit gets billions of pageviews monthly – and about building features that millions of users actually love.

Interview Structure

Initial Screen (30 minutes):

  • Recruiter call to discuss background
  • Talk about why Reddit
  • Salary expectations
  • Timeline and logistics

Technical Phone Screen (45-60 minutes):

  • 1-2 coding problems
  • Live coding in CoderPad
  • Medium leetcode difficulty
  • Some discussion about your experience

My phone screen: Implement a rate limiter, then discuss how I’d deploy it at Reddit scale. Good indicator of their focus.

Virtual Onsite (4 hours):

  • 2 coding rounds (45 min each)
  • 1 system design round (60 min)
  • 1 behavioral/culture fit round (30 min)
  • 15 min break between rounds

Technical Focus Areas

1. Data Structures & Algorithms (Core)

Medium to hard leetcode:

  • Trees and graphs (BFS, DFS)
  • Hash tables and sets
  • String manipulation
  • Some DP (not super heavy)
  • Sliding window, two pointers

They want efficient solutions. Brute force won’t cut it.

2. System Design (Very Important)

Expect Reddit-scale problems:

  • Design a voting system (upvotes/downvotes)
  • Design a comment tree structure
  • Design a feed generation system
  • Design a notification service
  • Caching strategies at massive scale

Focus on:

  • Handling millions of concurrent users
  • Data consistency vs availability tradeoffs
  • Caching strategies (Redis heavily used at Reddit)
  • Database sharding and replication

3. Python/Backend Skills

Reddit is heavily Python-based (though they’re adding more Go):

  • Strong Python knowledge expected
  • Web frameworks (Flask/Django)
  • REST API design
  • Database optimization
  • Caching patterns

Coding Interview Details

Round 1 – Data Structures:

Problem I got: “Implement a comment tree where you can efficiently fetch all child comments of a given comment.”

They wanted:

  • Tree traversal algorithm
  • Discussion of time/space complexity
  • How to optimize for Reddit’s use case (millions of comments)
  • Database schema design

Round 2 – Algorithms:

Problem: “Given user voting history, detect vote manipulation (bots).”

Required:

  • Pattern detection algorithms
  • Statistical analysis
  • Handling large datasets efficiently
  • Practical tradeoffs (false positives vs false negatives)

This is typical Reddit – real problems they actually face.

System Design Interview

Question: “Design Reddit’s voting system to handle 10 million votes per minute.”

Key areas to cover:

  1. Data Model:
    • How to store votes
    • Denormalization for performance
    • Score calculation
  2. Scale:
    • Database sharding strategy
    • Caching layer (Redis)
    • Queue for async processing
  3. Consistency:
    • Eventual consistency acceptable?
    • How to handle conflicts
    • Vote fraud prevention
  4. Performance:
    • Read vs write optimization
    • Caching strategies
    • CDN usage

The interviewer pushed hard on specifics – “How exactly would you shard? What happens if a shard goes down? How do you ensure vote counts are accurate?”

Behavioral Interview

Reddit has a strong engineering culture. They look for:

  • Passion for the product: Actually use Reddit, have opinions
  • User focus: Care about the community
  • Pragmatism: Ship features, don’t overengineer
  • Collaboration: Work well with product/design

Questions I got:

  • “Tell me about a time you disagreed with a product decision.”
  • “How do you handle technical debt?”
  • “Describe a feature you shipped that users loved.”
  • “What would you improve about Reddit?”

That last one is important – have real, thoughtful suggestions ready.

Preparation Strategy

For Coding (3-4 weeks):

  • 100+ leetcode problems (focus on medium)
  • Emphasize trees, graphs, hash tables
  • Practice live coding – they’ll watch you think
  • Write clean, commented code

For System Design (2-3 weeks):

  • Study Reddit’s architecture (tech talks, blog posts)
  • Understand caching patterns deeply
  • Learn about database sharding
  • Practice designing social features

For Behavioral (1 week):

  • Use Reddit daily, note what works/doesn’t
  • Prepare STAR stories
  • Think about scale problems
  • Have thoughtful product opinions

Difficulty: 7.5/10

Comparable to mid-tier FAANG. Easier than Google/Meta (9/10), harder than most Series B startups (6/10).

The coding is standard leetcode medium. The system design is where they really test you – expect to go deep on scale and caching.

Compensation (2024 data)

  • New grad: $140-160K base + $40-60K stock
  • Mid-level (3-5 YOE): $160-200K base + $60-100K stock
  • Senior (5-8 YOE): $200-260K base + $100-200K stock
  • Staff+: $280-400K+ total comp

Stock vests over 4 years. 10-15% annual bonus. Post-IPO, stock is liquid.

Culture & Work Environment

Pros:

  • Smart, passionate engineers
  • Interesting technical challenges at scale
  • Product people actually care about users
  • Remote-friendly (really!)
  • Good work-life balance (45 hours/week typical)

Cons:

  • Lots of legacy code (site is 18+ years old)
  • Some tech debt
  • Not as much $$ as FAANG
  • Post-IPO pressure to grow revenue

Things That Surprised Me

  1. Technical rigor: Harder than I expected for a “social media” company
  2. Scale focus: Every question had a scale component
  3. Python everywhere: They really care about Python skills
  4. Product involvement: Engineers have strong product opinions

Red Flags to Watch

  • Ask about on-call rotation (can be heavy for some teams)
  • Ask about technical debt (varies by team)
  • Ask about team stability (some teams have higher turnover)
  • Ask about roadmap (post-IPO priorities shifting)

My Experience

Did well on coding rounds – solved both problems optimally with clean code. System design was challenging but I covered the main areas. Behavioral went great – I’m an active Reddit user so had genuine enthusiasm.

Got the offer but ended up going elsewhere for more money. Would’ve been happy at Reddit though – seemed like a good place to work on real scale problems.

Tips for Success

  1. Actually use Reddit: Browse different subreddits, notice patterns, have opinions
  2. Focus on scale: Every answer should consider “what if 10M users?”
  3. Know caching: Redis comes up a lot in system design
  4. Write clean code: They care about code quality
  5. Be pragmatic: They want builders, not perfectionists
  6. Ask good questions: About team, tech stack, roadmap

Resources That Helped

  • Reddit Engineering Blog (redditblog.com)
  • System Design Primer (GitHub)
  • Grokking the System Design Interview
  • Leetcode premium (for Reddit-specific questions)
  • Redis documentation (seriously, know Redis)

Reddit is a solid choice if you want to work on real scale problems, care about community, and want better work-life balance than FAANG. The interview is tough but fair – prepare well and you’ll do fine.

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