Principal Software Engineer (Core Services)

Location: San Mateo, California, United States. Office-based roles are onsite Tuesday, Wednesday, and Thursday, with optional presence on Monday and Friday.

Salary: $345,040–$399,420 USD annual base pay, plus potential equity and benefits.

Company

Roblox builds tools and platform infrastructure for developers and creators to produce shared 3D digital experiences.

What you will do

• Build and evolve shared C#/.NET and Rust frameworks, libraries, SDKs, and runtime integrations.
• Develop HTTP/gRPC infrastructure, caching, configuration, observability, and reusable service components.
• Investigate application and runtime performance, including allocation pressure, garbage collection, lock contention, asynchronous execution, serialization, and network overhead.
• Design safe managed/native interoperability with clear ownership, error handling, cancellation, and compatibility contracts.
• Create automation for framework upgrades and service migrations, including AI-assisted workflows, compatibility tests, benchmarks, traffic replay, and canary validation.
• Lead ambiguous technical initiatives, mentor engineers, and coordinate safe adoption and rollout of shared platform changes.

Requirements

• Deep production experience with C#/.NET or Rust and the ability to work across both ecosystems.
• Experience building reusable libraries, SDKs, frameworks, or runtime infrastructure adopted by multiple teams.
• Strong knowledge of concurrency, asynchronous programming, memory management, networking, and distributed systems.
• Experience diagnosing complex production issues and delivering measurable performance or reliability improvements.
• Experience with API design, compatibility, versioning, dependencies, and adoption across dependent systems.
• Demonstrated technical leadership, stakeholder alignment, mentoring, and cross-team execution; a computer science degree or equivalent experience.

Nice to have

• .NET runtime internals, garbage collection and allocation optimization, thread-pool behavior, or production profiling.
• Rust ownership and lifetimes, asynchronous runtimes, concurrent data structures, or performance-sensitive library design.
• Managed/native interoperability, FFI, native memory diagnostics, or cross-platform packaging.
• Contract-driven code generation, serialization, compatibility testing, or large-scale framework migrations.
• Automated validation and rollout of shared dependencies across a service fleet.

Culture & Benefits

• Work on foundational infrastructure used across Roblox's service fleet.
• Full-time employees are eligible for equity compensation and benefits.
• US work authorization may be required for certain visa categories, and future H-1B sponsorship may not be supported.
• Reasonable accommodations are available during the recruiting process for qualifying disabilities or religious beliefs.