Reddit Engineering Manager Interview Questions

1.Tell me about a time you had to choose between a quick, hacky solution and a more elegant long-term fix. How did you make that decision and what was the outcome?

2.Tell me about the largest system or team scaling challenge you've managed. What did you do differently as a manager compared to when you were an individual contributor?

3.Tell me about a time your team faced a major traffic spike or scaling challenge. How did you manage the technical response and keep your team focused during the incident?

4.Describe a time when you advocated for a feature or technical change that would give users more control over their experience, even if it made your engineering work more complex. What was your reasoning?

5.Describe a time when you had to make an engineering decision that would significantly impact how communities or moderators used your product. How did you factor community needs into your technical choices?

6.Walk me through a time you led your team in building a system that needed to handle bad actors or abuse at scale. What were your main concerns and how did you address them architecturally?

7.A junior engineer on your team wants to add a new API endpoint that joins data from three different microservices. How do you guide them through this decision?

8.Walk me through how you'd design the database schema and API for Reddit's new community awards feature, where users can give custom awards specific to each subreddit.

9.You need to design a caching layer for Reddit's comment ranking system that serves millions of requests per second. Walk me through your approach and what tradeoffs you'd make.

10.Your team maintains Reddit's search infrastructure that handles millions of queries daily. A PM wants to add semantic search capabilities. How do you evaluate and plan this technical investment?

11.Reddit's recommendation feed needs to balance showing users fresh content versus personalized content they're likely to engage with. How would you approach the ML engineering challenges here?

12.Your team is responsible for Reddit's mobile push notification system. Users are complaining about getting too many irrelevant notifications. How do you approach fixing this both technically and organizationally?

13.Reddit's web platform needs to display upvote counts that update in real-time for millions of concurrent users. Design the system that keeps vote displays consistent while handling Reddit's traffic scale.

14.Design Reddit's real-time chat infrastructure for both direct messages and live community discussions, handling millions of concurrent conversations while preventing spam and maintaining message ordering.

15.Design Reddit's content moderation pipeline that processes millions of posts and comments daily, automatically flagging potential violations while giving moderators the tools they need to make final decisions.

16.Reddit needs to redesign its ads targeting system to respect user privacy while still delivering relevant ads across millions of communities. Walk me through your technical approach.

17.Design the infrastructure for Reddit's experimentation platform that needs to run hundreds of concurrent A/B tests across billions of pageviews while ensuring statistical validity and avoiding cross-experiment contamination.

18.Reddit is building a global content distribution system to serve posts, images, and videos to users worldwide while complying with different countries' content regulations. How would you architect this system?

19.Tell me about a time you had to influence a senior engineer or staff engineer to change their technical approach when you weren't their direct manager. How did you build that alignment?

20.Describe a time when you inherited a team where engineers had different opinions about the right technical direction. How did you navigate that and drive alignment?

21.Walk me through a time when you had to lead your team through a major platform migration or architectural change. How did you maintain team morale and delivery velocity during the transition?

22.Tell me about a time when you had to advocate upward to senior leadership for an engineering decision that didn't have obvious business value but was important for technical health or team effectiveness.

23.Describe a situation where you had to manage an engineer whose work output was solid but whose communication style was creating friction with other teams or community-facing partners. How did you address this?

24.Tell me about a time when you had to make a difficult people decision—like role changes, performance management, or team restructuring—that you knew would be unpopular but was necessary for team effectiveness.

25.Reddit's daily active users dropped 3% over the past month, but our engagement metrics like comments per post and time spent are actually up. Walk me through how you'd investigate this and what hypotheses you'd test first.

26.Estimate how many moderator actions happen on Reddit per day across all communities, and walk me through your calculation. Then tell me what infrastructure considerations this creates.

27.Reddit wants to expand into a new international market where users primarily browse on low-end Android devices with limited data plans. Walk me through how you'd estimate the engineering investment needed and what success metrics you'd track.

28.A popular subreddit with 2 million subscribers is complaining that their posts aren't getting the visibility they used to have in users' feeds. The community is threatening to migrate to another platform. How do you approach diagnosing and addressing this?

29.Reddit is considering offering a premium tier that gives certain communities access to advanced analytics about their member engagement and growth. Estimate the potential annual revenue and walk me through the key assumptions in your model.

30.Reddit's mobile app crash rate spiked to 2.1% last week, up from our usual 0.8%. User reviews are complaining and our app store ratings dropped. You have limited engineering resources to investigate. Walk me through how you'd prioritize and tackle this.