Scale Engineer

Software Engineer III

Software EngineerIC3Medium to Hard

This interview process is designed to assess candidates for the Software Engineer III (IC3) role at Reddit. It evaluates technical proficiency, problem-solving skills, system design capabilities, and cultural fit within the company.

Rounds·3

Timeline·~14d

Experience·4 - 7 yrs

Comp band·US$140000 - US$180000

Interview time·150 min

Evaluation

What they measure.

  • Problem-solving approach and analytical skills.
  • Data structures and algorithms knowledge.
  • Coding proficiency and best practices.
  • System design and architectural thinking.
  • Communication and collaboration skills.
  • Cultural fit and alignment with Reddit's values.

Preparation

How to prepare.

Tips

  1. Review fundamental data structures and algorithms (arrays, linked lists, trees, graphs, hash maps, sorting, searching).
  2. Practice coding problems on platforms like LeetCode, HackerRank, or similar.
  3. Study system design principles for scalable applications (databases, caching, load balancing, message queues, microservices).
  4. Understand common software engineering concepts like OOP, design patterns, testing, and debugging.
  5. Research Reddit's products, values, and recent news.
  6. Prepare behavioral questions using the STAR method (Situation, Task, Action, Result).
  7. Practice explaining your thought process clearly and concisely.
  8. Prepare questions to ask the interviewer about the role, team, and company culture.

Study plan

Fig · Study plan — 06 phases

01 / 06
01

Phase 01 of 06

Data Structures and Algorithms

Weeks 1-2: Data Structures & Algorithms Fundamentals. Practice medium LeetCode.

Weeks 1-2: Focus on core data structures (arrays, linked lists, stacks, queues, hash tables) and algorithms (sorting, searching, recursion, dynamic programming). Practice medium-difficulty problems on LeetCode.

Questions

Commonly asked.

  • Design a system to handle Reddit's feed.
  • How would you implement a real-time commenting system?
  • Given a large dataset of user activity, how would you identify trending topics?
  • Describe a challenging technical problem you solved.
  • How do you ensure the scalability and reliability of your code?
  • What are your thoughts on the trade-offs between different database technologies?
  • Tell me about a time you mentored a junior engineer.
  • How do you approach code reviews?
  • What are your favorite programming languages and why?
  • How would you optimize the performance of a slow API endpoint?

Locations

Regional differences.

Fig · Regions — 02 locations

01 / 02

Location

San Francisco, USA

Interview focus

System design for large-scale social platforms.Understanding of distributed systems and scalability.Experience with real-time data processing.Collaboration and communication skills in a remote or hybrid environment.

Common questions

  • How would you design a URL shortener for Reddit?
  • Discuss a time you had to deal with a difficult stakeholder.
  • What are the trade-offs between SQL and NoSQL databases for a social media platform?
  • Describe a complex bug you encountered and how you debugged it.

Tips

  • Familiarize yourself with Reddit's architecture and common technologies used.
  • Prepare examples of leading projects and mentoring junior engineers.
  • Be ready to discuss your experience with A/B testing and feature rollouts.
  • Highlight any experience with internationalization or localization if applicable to the role.

Rounds

Round-by-round.

Expand a step for evaluation criteria, sample questions, and prep notes.

DSA

Coding questions at Reddit.

Frequently reported on Reddit loops

View all at Reddit

Other guides

More at Reddit.