Roblox DevOps / SRE Interview Questions

Behavioral Questions (15)

1. 1.Walk me through a time you supported a platform or API that external developers depended on. How did you handle a change that could have broken their integrations?

   easy~3 min

   What interviewers look for

   • Demonstrates understanding of backward compatibility and API versioning principles
   • Shows communication strategy with external developers about changes
   • Describes testing or validation with actual developer use cases
   • Mentions monitoring developer adoption and rollback planning

   Likely follow-ups

   • How did you communicate the timeline to affected developers?
   • What monitoring did you put in place to catch integration issues?
   • How did you prioritize which developer concerns to address first?

   Company context

   Roblox's Developer Ecosystem principle recognizes that creators have earned over $1 billion on the platform, making API stability critical for their livelihoods. SREs must ensure that infrastructure changes don't break Studio tools, marketplace APIs, or revenue-sharing systems that developers depend on. The 'Take the Long View' value means prioritizing developer trust over short-term operational convenience.

2. 2.You're managing game server deployments for Roblox, and we need to roll out a physics engine update to thousands of running game instances without dropping active players. How would you orchestrate this deployment?

   easy~3 min

   What interviewers look for

   • Discusses session persistence and player state management during rolling updates
   • Mentions canary deployments or blue-green strategies for game servers
   • Considers cross-platform compatibility testing before rollout

   Likely follow-ups

   • What would you do if the new physics engine caused frame rate drops on mobile devices specifically?
   • How would you handle a scenario where the update breaks deterministic simulation for certain game types?

   Company context

   Roblox runs thousands of concurrent game servers hosting real-time multiplayer experiences. The 'Get Stuff Done' value requires shipping updates quickly, but the platform's commitment to developers means deployments can't disrupt active gameplay sessions or break experience compatibility.

3. 3.Design a logging and monitoring system for Roblox's real-time multiplayer game servers that need to track both system health and in-game events like player interactions and economy transactions. How do you handle the data volume from thousands of concurrent game instances?

   easy~3 min

   What interviewers look for

   • Proposes tiered logging strategy with different retention periods for system vs game events, understanding that economy transactions need longer retention for fraud detection
   • Addresses sampling and aggregation strategies to handle high-volume real-time data without impacting game server performance
   • Considers how to correlate system metrics with game events to debug issues like lag spikes affecting player experience

   Likely follow-ups

   • How would you handle logging when a game server becomes unresponsive but players are still connected?
   • What metrics would you prioritize for alerting when Robux transactions start failing in a specific game?

   Company context

   Roblox operates thousands of game server instances simultaneously, each handling real-time multiplayer experiences and Robux economy transactions. The platform's 'Respect the Community' value requires robust monitoring to detect safety issues, while 'Get Stuff Done' demands that logging infrastructure doesn't impact game performance. This tests understanding of Roblox's unique scale where system health and user experience are deeply intertwined.

4. 4.Tell me about a time you had to convince multiple engineering teams to adopt a new infrastructure standard or practice when they were initially resistant. What was your approach and how did you measure success?

   easy~3 min

5. 5.Roblox Studio crashes are blocking developers from publishing their experiences, costing us roughly $50K per hour in lost developer revenue. You need to estimate how much we should invest in a redundant Studio backend service. Walk me through your cost-benefit analysis.

   easy~3 min

6. 6.Tell me about a time you had to optimize infrastructure to reduce latency for real-time applications. What was the latency target, what approach did you take, and what was the impact?

   medium~4 min

7. 7.Our Kubernetes clusters are running game server pods that need extremely low latency networking between them for spatial audio. You're seeing inconsistent pod-to-pod latency that's affecting voice chat quality. How do you debug and fix this?

   medium~4 min

8. 8.Roblox Studio needs to sync project files and assets between creators' local machines and our cloud storage, supporting offline editing and real-time collaboration. Design the synchronization system that handles conflicts when multiple developers work on the same experience.

   medium~4 min

9. 9.Describe a situation where you had to balance supporting the immediate needs of game developers on the platform versus making infrastructure improvements that would benefit the broader ecosystem. How did you navigate that tension?

   medium~4 min

10. 10.We're seeing 15% higher game server CPU usage during school holidays, but our auto-scaling isn't keeping up and we're getting player complaints about lag. How would you investigate what's driving the increased resource consumption?

    medium~4 min

11. 11.Describe a time you implemented monitoring or safeguards to protect users in a system where user-generated content could cause harm. What specific risks were you trying to prevent?

    hard~5 min

12. 12.We're seeing MongoDB write hotspots during peak hours when millions of developers are simultaneously publishing updates to their experiences in Roblox Studio. The database is sharded by developer_id, but some developers are much more active than others. How would you redesign the sharding strategy?

    hard~5 min

13. 13.Design a real-time content moderation pipeline that can analyze text, voice, and 3D assets uploaded to Roblox experiences, with the constraint that false positives blocking legitimate creator content directly hurt platform revenue. How do you balance safety with creator experience?

    hard~5 min

14. 14.Walk me through a time when you had to lead a cross-functional initiative that required coordinating between platform infrastructure, trust and safety systems, and developer-facing services. What made this particularly challenging and how did you ensure alignment?

    hard~5 min

15. 15.Estimate how many additional game servers Roblox would need if we enabled voice chat in all experiences by default, assuming current adoption rates and hardware constraints. What are your key assumptions and how would you validate them?

    hard~5 min