Senior Software Engineer, Product at Arena

ABOUT ARENA INTELLIGENCE 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. ABOUT THE ROLE We're looking for a Senior Software Engineer to own features end-to-end across Arena's platform — from understanding the problem, through designing and building the solution, to shipping it, measuring its impact, and iterating. This is a hands-on IC role for someone who writes code every day, cares deeply about what happens after launch, and is excited to shape how people interact with cutting-edge AI. YOU’LL - Own features from technical scoping through deployment and post-launch iteration — not just build them, but make sure they work - Design and extend schemas, APIs, and business logic to support new product capabilities - Ship high-quality product code across the stack - Incorporate real user feedback — from data, direct user contact, or your own product instincts — to improve what you've shipped - Work closely with ML researchers to turn research services to production, making them consumable for product development - Collaborate across design, product, and engineering to figure out what to build, not just how - Identify and advocate for improvements to development, testing, and deployment practices YOU’LL HAVE - 4+ years of experience in software engineering, with a focus on product development - Experience building user-facing web applications spanning frontend, backend/API, and database — in any stack. You understand the request lifecycle across layers - Clear, concise communication — you explain technical decisions well, distinguish your work from the team's, and proactively share context - Evidence of shipping and iterating — you can describe the full arc of a feature you owned: problem, solution, code, what happened after launch, and what you'd change now - A product engineering identity — you care about whether the thing you built actually worked for users, not just whether the code was clean - Genuine curiosity about AI evaluation and Arena's mission — you've looked at the product and can articulate why this domain matters to you BONUS EXPERIENCE - Familiarity with our stack: NextJS, React, TypeScript, Tailwind, ShadCN, HonoJS, Postgres, Vitest - Experience with Supabase or Vercel's AI SDK - You've shipped without PM or design support — determined what to build by talking to users or looking at data OUR TECH STACK: - NextJS - React + TypeScript - Tailwind + ShadCN - HonoJS - Postgres - Vitest WHAT WE OFFER - We offer competitive compensation and equity aligned to the markets where our team members are based. The base salary range will depend on the candidate’s permanent work location. - 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 Come help build the space where anyone can explore and help shape the future of AI. Arena Intelligence provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, color, religion, sex, national origin, age, disability, genetics, sexual orientation, gender identity, or gender expression. We are committed to a diverse and inclusive workforce and welcome people from all backgrounds, experiences, perspectives, and abilities.