Senior Software Engineer, Full Stack

Arena Intelligence is the open platform for evaluating how AI models perform in the real world. Created by researchers from UC Berkeley’s SkyLab, our mission is to measure and advance the frontier of AI for real-world use.

Millions of people use Arena Intelligence each month to explore how frontier systems perform — and we use our community’s feedback to build transparent, rigorous, and human-centered model evaluations. Leading enterprises and AI labs rely on our evaluations to understand real-world reliability, alignment, and impact. Our leaderboards are the gold standard for AI performance — trusted by leaders across the AI community and shaping the global conversation on model reliability and progress.

We’re a team of researchers, engineers, academics, and builders from places like UC Berkeley, Google, Stanford, DeepMind, and Discord. We seek truth, move fast, and value craftsmanship, curiosity, and impact over hierarchy. We’re building a company where thoughtful, curious people from all backgrounds can do their best work. Everyone on our team is a deep expert in their field — our office radiates excellence, energy, and focus.

LMArena is seeking a Senior Full-Stack Product Engineer to lead the technical design and development of AI-focused products across our platform. You’ll be responsible for owning features end-to-end—from proposing technical approaches and implementing core product flows, to deploying new functionality and tracking its impact. This role is ideal for someone with proven experience building reliable business logic at scale who is excited to shape how people interact with cutting-edge AI models.