Fullstack Software Engineer (AI)

Location: Bay Area, United States; hybrid

Company

Arena is an AI evaluation platform that measures how frontier models perform in real-world workflows and provides transparent datasets and evaluations for AI labs, enterprises, and researchers.

What you will do

• Own product features end-to-end, from technical scoping and implementation through deployment, measurement, and post-launch iteration.
• Design and extend schemas, APIs, and business logic for new platform capabilities.
• Ship high-quality product code across the frontend and backend.
• Use user feedback, product data, and direct user contact to improve shipped features.
• Work with ML researchers to productionize research services for product development.
• Collaborate with design, product, and engineering while improving development, testing, and deployment practices.

Requirements

• 3+ years of software engineering experience, especially with enterprise or developer-facing products.
• Experience building user-facing web applications across frontend, backend/API, and database layers.
• Ability to explain technical decisions clearly and communicate ownership and context proactively.
• Evidence of shipping, measuring, and iterating on features after launch.
• Product engineering mindset focused on whether software works for users.
• Genuine interest in AI evaluation and Arena's mission.

Nice to have

• Familiarity with Next.js, React, TypeScript, Tailwind, ShadCN, HonoJS, Postgres, and Vitest.
• Experience with Supabase or Vercel's AI SDK.
• Experience defining and shipping products without dedicated product manager or design support.

Culture & Benefits

• Competitive compensation and equity aligned with the market where the employee is based.
• Comprehensive medical, dental, vision, and additional health and wellness benefits.
• Opportunity to work on cutting-edge AI with a small, mission-driven team.
• Culture centered on transparency, trust, craftsmanship, curiosity, and community impact.