Roblox
Roblox Senior Software Engineer Interview
Focus areas and question themes aggregated from 14 current openings — pick any opening below and practice a voice mock calibrated to it.
Roblox Senior Software Engineer mock interview
A live voice mock calibrated to this role — real questions, the real follow-up rhythm, and a score at the end. Free to start.
Roblox's Senior Software Engineer family runs from deep C++ engine work - the DataModel scenegraph, avatar animation, client performance - to backend infrastructure teams rebuilding caching, service mesh, and Kubernetes networking at billion-user scale. A striking number of these postings are for brand-new or newly-forming teams (Kubernetes Networking, Avatar Defaults, the in-engine Ads system, Service Mesh), so expect questions about founding architecture from zero rather than maintaining an inherited system. Whether the stack is C++ or Go, the postings consistently want concrete, metrics-grounded stories from real production work.
What this interview tests
- Deep C++ systems and engine engineering — App Performance, Game Engine Systems (the DataModel), Avatar Defaults, Ads Experience, and UGC Validation all test hands-on C++ depth - memory layout, smart pointers, templates, and virtual functions - applied to a live game engine running on everything from low-end mobile to console.
- Distributed infrastructure at Roblox's real scale — Storage Cache (ValKey at up to 1B DAU), Ads Platform, and Data Infrastructure (Kafka/Flink/Spark/Trino/Druid/Airflow processing petabytes daily) all center interviews on distributed-systems tradeoffs - isolation, hot-key mitigation, query planning - grounded in Roblox's actual scale numbers rather than abstract systems trivia.
- Founding architecture on brand-new teams — Kubernetes Networking, Avatar Defaults, Ads Experience, and Service Mesh are all explicitly newly-formed or ground-floor teams, so interviewers probe how candidates set technical direction and establish standards where no precedent exists yet, not just execute an existing roadmap.
- Cross-device and cross-tier performance reasoning — App Performance, Game Engine Systems, and Avatar Defaults all require reasoning about the same feature running acceptably on mobile, desktop, and console simultaneously, with concrete before/after performance metrics expected in answers.
- Mentoring and driving direction without formal authority — Storage Cache, Ads Platform, Data Infrastructure, Kubernetes Networking, and Service Mesh all explicitly ask how candidates mentor engineers or drive architectural standards across a team, a recurring senior-IC expectation independent of the specific tech stack.
- Domain-specific technical depth — Some postings carry a hard specialization filter beyond general backend or engine skill - NPC Behavior wants LLM/imitation-learning/behavior-tree judgment, UGC Validation wants mesh and rigging/skinning-weight geometry processing, and Game Solutions wants multiplayer client/server-authority networking plus the ability to advise external studios directly.
Common question themes
Walk through the hardest C++ performance bug or bottleneck you diagnosed and fixed, with concrete before-and-after metrics.
Grounded in the App Performance, Ads Experience, and Game Engine Systems postings, all of which explicitly ask for a specific past bug with real numbers.
Design a distributed system - a cache, an ads-serving pipeline, a data platform - that has to hold up at Roblox's real scale (hundreds of millions of users, petabytes of daily data).
Reflects the Storage Cache, Ads Platform, and Data Infrastructure postings, which all frame the system-design round around Roblox's actual production scale rather than a hypothetical.
Tell me about setting technical direction or establishing architecture standards on a team with no existing precedent to follow.
Directly grounded in the Kubernetes Networking, Avatar Defaults, and Service Mesh postings, all explicitly newly-formed teams building from zero.
How do you reason about performance tradeoffs when the same code has to run acceptably on low-end mobile, desktop, and console?
Comes from the App Performance, Game Engine Systems, and Avatar Defaults postings, which all frame cross-device performance as a first-class design constraint.
Describe mentoring an engineer or driving an architectural decision on a team, without having formal authority over it.
Named across the Storage Cache, Ads Platform, Data Infrastructure, and Kubernetes Networking postings as a distinct senior-level expectation.
Walk through a production incident you owned - a hot-key contention issue, an mTLS or sidecar-injection failure, a partial-failure bug - and how you traced it.
Grounded in the Storage Cache and Service Mesh postings, both of which describe on-call ownership of critical infrastructure.
How do you take a feature from prototype through to a production rollout used by millions of experiences?
Reflects the Avatar Defaults and Ads Experience postings, both of which frame this prototype-to-scale path as central to the role.
Go deep on a domain-specific problem matched to the team - choosing between LLM, imitation learning, or behavior trees for an NPC, or detecting a geometry-based exploit in a 3D asset.
This family's postings specialize heavily by team (NPC Behavior, UGC Validation), so the deep-dive question is tailored to that team's actual technical problem.
Likely format
None of the postings in this family specify an interview format, so there's no confirmed round count or structure to report. Based purely on question style, expect the loop to lean on detailed walkthroughs of real past projects with concrete metrics - performance numbers, scale figures, production incidents - rather than abstract or generic algorithm questions, since nearly every posting asks for a specific bug, system, or decision you actually shipped.
All 14 Roblox openings in this role
Roblox
Senior
Senior Software Engineer, App Performance
Roblox
Senior
Senior Software Engineer, Game Engine Systems
Roblox
Senior
Senior Software Engineer
Roblox
Senior
Senior Software Engineer - Avatar Defaults
Roblox
Senior
Senior Software Engineer, NPC Behavior
Roblox
Senior
Senior Software Engineer, Storage Cache
Roblox
Senior
Senior Software Engineer, Ads Experience (C++)
Roblox
Senior
Senior Software Engineer, Ads Platform
Roblox
Senior
Senior Software Engineer, Data Infrastructure
Roblox
Senior
Senior Software Engineer, Game Solutions
Roblox
Senior
Senior Software Engineer, Kubernetes Networking
Roblox
Senior
Senior Software Engineer, Safety Foundation
Roblox
Senior
Senior Software Engineer, Service Mesh
Roblox
Senior
Senior Software Engineer, UGC Validation
Frequently asked questions
Does every role in this family require deep C++ expertise?
No. Engine-facing roles like App Performance, Game Engine Systems, Avatar Defaults, Ads Experience, and UGC Validation all require hands-on C++ systems depth, but several postings - Storage Cache, Safety Foundation, Kubernetes Networking, Service Mesh - are backend and infrastructure roles built primarily in Go and Kubernetes with no C++ requirement at all.
Are a lot of these Roblox Senior Software Engineer roles on brand-new teams?
Yes, notably so. Kubernetes Networking is described as founding a networking domain from scratch, Avatar Defaults is a newly forming team, the Ads Experience posting is building an ads system from the ground floor of a new business line, and Service Mesh and the India-based ROS team are similarly early-stage. Expect more questions about establishing precedent than maintaining an inherited system.
What does the actual Roblox interview loop look like for this role family?
None of the postings describe the loop structure, so there's nothing confirmed to report on round count or format. What is consistent is the expectation that candidates can walk through specific, metrics-backed past work rather than answer generic or hypothetical questions.