Senior Software Engineer, Runtime

About the role

At Roblox, we’re building the tools and platform that empower our global community of developers and creators to bring any experience they can imagine to life. The Game Engine team works on the systems that power the experiences at the heart of the metaverse. Our code is the technical foundation in our client, editor, and simulation servers.

The Runtime Pod builds and maintains the foundational C++ components that power the entire Roblox Engine and Studio stack. We own the Runtime layer—the performance, efficiency, and usability of the core primitives that every other engineering team relies on. Think of Runtime as the “standard library” and execution engine for Roblox's C++ world. Our ownership centers on three pillars:

• Concurrency System – our task scheduler and fiber runtime power how work is parallelized across CPU cores, letting teams scale features across platforms while keeping code understandable and debuggable.
• Memory System – we own the engine's memory allocator stack, tracking pipelines, and observability tooling to make memory behavior predictable and prevent leaks and fragmentation.
• Profiling and Observability – we build and evolve the MicroProfiler and telemetry pipelines to help engineers diagnose real-world regressions and keep the client fast at global scale.

This role centers on our Concurrency system. You will own the scheduler and fiber runtime that the rest of the engine is built on, research and implement the performance work needed for 3K-player servers and genre expansion initiatives, and act as the point of contact other engine teams come to with concurrency asks. You will debug real production failures across PC, Mac, mobile, and console, and build deep intuition for how compilers, CPU architectures, and operating systems interact.

Responsibilities

• Take ownership of part of the engine's Concurrency system—the task scheduler, fiber runtime, and async APIs that every other engine team builds on.
• Research and implement performance improvements that unblock platform initiatives—unlocking higher fidelity and richer experiences.
• Serve as a point of contact for concurrency across the org: design reviews, hard parallelism bugs, and asks from other engine teams.
• Improve the ergonomics, testability, and debuggability of concurrent code across PC, Mac, mobile, and console.

Requirements

• Strong modern C++ (C++17 or newer) in a large, complex production codebase.
• Deep multithreading/concurrency experience—schedulers, thread pools, lock-free programming, atomics, memory models.
• Comfort profiling and reasoning about performance at the OS/CPU level.

Nice to Have

• Game engine or real-time systems experience.
• Fiber/coroutine runtimes, work-stealing or job-system schedulers.
• Cross-platform low-level development (Android, iOS, console).
• Track record as the go-to expert other teams consult on a system.

Pay

For roles based at our headquarters in San Mateo, CA, the starting base pay range is $196,750—$243,290 USD. The actual base pay is dependent upon professional background, training, work experience, location, business needs, and market demand.

Schedule

Roles that are based in an office are onsite Tuesday, Wednesday, and Thursday, with optional presence on Monday and Friday.

Benefits

All full-time employees are eligible for equity compensation and benefits as described on our careers page.