Senior Infrastructure Engineer Job at Arena Intelligence, Inc. (Bay Area)

Senior Infrastructure Engineer

Arena Intelligence, Inc.

Location:
United States , Bay Area

Category:
IT - Software Development

Contract Type:
Not provided

Salary:

Not provided

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Job Description:

LMArena is seeking a Senior Infrastructure Engineer to define, build, and evolve the technical foundations that power the world’s most transparent AI evaluation platform. This is not just an architecture role - you’ll partner directly with product, security, and data teams to identify bottlenecks, design resilient systems, and ship the code that keeps our platform fast, reliable, and secure at scale. You’ll have a broad impact across the stack: optimizing performance, building primitives that accelerate feature delivery, hardening our systems against abuse, and scaling infrastructure to handle billions of API requests and real-time votes. If you love working across boundaries, getting deep into code, and making infrastructure a product in its own right, this is the role for you.

Job Responsibility:

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

Requirements:

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

Nice to have:

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

What we offer:

Comprehensive health and wellness benefits, including medical, dental, vision, and additional support programs
The opportunity to work on cutting-edge AI with a small, mission-driven team
A culture that values transparency, trust, and community impact

Additional Information:

Job Posted:
February 20, 2026

Employment Type:

Fulltime

Work Type:

Hybrid work

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