LMArena · 1 month ago
Senior Infrastructure Engineer
San Francisco Bay Area
Full-time
Onsite
Senior Level, Lead/Staff
8+ years expLMArena is an innovative platform focused on evaluating AI model performance in real-world scenarios. They are seeking a Senior Infrastructure Engineer to build and enhance the technical foundations of their platform, collaborating with various teams to optimize performance and ensure security at scale.
Artificial Intelligence (AI)Information ServicesMachine LearningProduct Research
Responsibilities
Own technical strategy for LMArena’s core infrastructure - networking, APIs, services, data systems, and security foundations
Design and implement high-performance systems that scale to hundreds of millions of real-time interactions and evaluations per day
Collaborate with security engineering to embed anti-abuse measures, Sybil resistance, and trust systems into core platform architecture
Partner with product engineering to deliver infrastructure improvements that directly accelerate feature velocity and reliability
Build developer-facing primitives and tooling—internal APIs, SDKs, CI/CD enhancements—that make our platform more productive and safe to build on
Monitor, profile, and optimize system performance across backend services, databases, and networking layers
Drive operational excellence through observability, capacity planning, and incident response best practices
Mentor engineers across the company in building scalable, performant, and secure systems
Qualification
Required
8+ years of experience in backend, infrastructure, or systems engineering, including staff-level scope in a high-scale production environment
Proven experience designing and operating distributed systems at scale (millions of DAU / billions of requests)
Deep knowledge of networking fundamentals, service-to-service communication, and traffic routing at scale
Hands-on experience with performance profiling, observability, and reliability engineering
Track record of collaborating with security and product engineering to deliver both foundational systems and user-facing features
Clear communicator who can lead technical discussions, build alignment across teams, and partner with us to prioritize the needs of the business
Preferred
Experience with Node.js, Typescript, Serverless Environments, Postgres
Background in anti-abuse systems, security engineering, or trust & safety platforms
Experience building infrastructure for real-time, user-driven platforms
Benefits
Comprehensive health and wellness benefits, including medical, dental, vision, and additional support programs.
Company
LMArena
LMArena is a web-based platform that evaluates large language models (LLMs) through anonymous, crowd-sourced pairwise comparisons.
11-50 employees
Funding
Current Stage
Early StageTotal Funding
$250M2026-01-06Series A· $150M
2025-05-21Seed· $100M
Leadership Team
Anastasios Angelopoulos
Chief Executive Officer
Recent News
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Company data provided by crunchbase