Senior Backend Engineer - Safety & Rules Engine

Every day, tens of millions of people come to Roblox to explore, create, play, and connect in 3D immersive digital experiences. Roblox's mission is to connect a billion people with optimism and civility, building safe and shared experiences for a global community of creators and players.

As a Senior Backend Engineer on the User Behavior team, you will build the core backend infrastructure that fundamentally transforms how Roblox responds to unsafe behavior—shifting from reactive, stateless punishments to a personalized, adaptive system based on a user's true risk profile. You will design, build, and operate a low-latency behavioral data layer, a centralized rules-and-inference decision engine, a unified feature restriction platform, and an LLM-assisted abuse reporting engine. Operating in Go, you will construct auditable, high-throughput backend services that protect hundreds of millions of users, particularly minors, across the platform.

Key Responsibilities

• User Behavior Data Layer: Architect and operate a low-latency, per-user data store that aggregates real-time signals (violation history, player reports, behavioral patterns) into a single, high-throughput queryable source of truth.
• Consequence Engine Architecture: Build and scale a centralized, deterministic rules-and-inference decision engine that integrates machine learning risk scores into a unified safety decision authoritative for all enforcement actions.
• Unified Feature Restriction Platform: Design a backend-driven intervention framework that enables product teams to plug in safety controls, replacing fragmented, feature-specific implementations.
• Consolidated Abuse Reporting System: Build scalable backend services unifying reporting channels—integrating LLM classification, agentic workflows, and ML routing to improve report prioritization, resolution speed, and global regulatory compliance.
• Auditable & Fair Serving Infrastructure: Build serving infrastructure that adheres to high standards of explainability, transparency, and auditing for all automated safety decisions.
• End-to-End Delivery: Own full software lifecycles in Go—from system architecture and API design to migration execution, monitoring, and production operations.

Requirements

Distributed Systems & Backend Engineering Depth

• 5+ years of professional experience building, scaling, and operating production backend services at scale using Go (or a comparable statically-typed backend language like C++, Rust, or Java).
• Distributed Systems Design: Deep hands-on experience designing high-concurrency microservices, gRPC/RPC APIs, event ingestion streams, caching tiers, and low-latency read/write paths.
• Rules Engines & State Systems: Experience architecting rules engines, workflow orchestration frameworks, or complex stateful business-logic services.
• Data Pipelines & ML Systems Integration: Experience with streaming or batch data ingestion pipelines feeding feature stores or data layers consumed by machine learning models.
• Production Operations: Solid fundamentals in monitoring, alerting, capacity planning, and on-call incident response for high-concurrency, user-facing systems.
• Ethical Systems Mindset: Commitment to building fair, auditable, and privacy-conscious software that safeguards user communities.

Preferred Qualifications

• Direct domain experience in Trust & Safety, fraud mitigation, risk modeling, or adversarial systems.
• Experience with real-time feature stores, ML inference serving infrastructure, or model deployment tools.
• Hands-on experience building server-driven UI or backend-driven notification and intervention rendering frameworks.

Total Rewards & Benefits

• Compensation & Equity: San Mateo base salary range ($196,750 – $243,290 USD) + competitive Roblox equity grants.
• Healthcare & Wellbeing: Comprehensive health, dental, and vision coverage for employees and dependents.
• Onsite Culture & Perks: Modern San Mateo headquarters with catered food, events, and collaboration spaces.
• Time Off & Retirement: Generous vacation policies, company holidays, paid parental leave, and 401(k) retirement options.