Location: SF Bay Area/Remote
Type: Full-Time
About the Role:
LMArena is seeking an experienced Senior Frontend Product Engineer to lead the design and development of intuitive, AI-focused user experiences across our platform. You’ll be responsible for owning features from proposing technical approaches and implementing core UI/UX flows, to deploying new functionality and tracking its impact through analytics. This role is ideal for someone who combines strong frontend craft with backend thinking, thrives on building polished user interfaces, and is excited to shape how people interact with cutting-edge AI models.
Responsibilities:
Lead development of UI and application logic for our chat interface using React and Next.js
Craft intuitive, accessible, and responsive user experiences that feel delightful across devices
Collaborate closely with design to maintain and extend a cohesive visual language and component system
Implement A11y accessibility standards and internationalization (i18n) support for a global audience
Expand backend data structures and business logic to support new frontend features
Plan and integrate analytics to measure user engagement, adoption, and product performance
Visualize feature performance and usage metrics through dashboards and internal tooling
Own the full feature lifecycle—from technical scoping to deployment and iteration based on insights
Who is LMArena?
Created by researchers from UC Berkeley’s SkyLab, LMArena is an open platform where everyone can easily access, explore and interact with the world’s leading AI models. By comparing them side by side and casting votes for the better response, the community helps shape a public leaderboard, making AI progress more transparent, and grounded in real-world usage.Why Join Us?
Trusted by organizations like Google, OpenAI, Meta, xAI, and more, LMArena is rapidly becoming essential infrastructure for transparent, human-centered AI evaluation at scale. With over one million monthly users and growing developer adoption, our impact is helping guide the next generation of safe, aligned AI systems—grounded in open access and collective feedback.
Our work is regularly referenced by industry leaders pushing the frontier of safe and reliable AI. Sundar Pichai, Jeff Dean, Elon Musk, and Sam Altman.
High Impact: Your work will be used daily by the world’s most advanced AI labs.
Global Reach: Develop data infrastructure powering millions of real-world evaluations, influencing AI reliability across industries at the top-tier
Exceptional Team: We are a small team of top talent from Google, DeepMind, Discord, Vercel, UC Berkeley, and Stanford.
Requirements:
5+ years of experience in software engineering, with a focus on full-stack or frontend product development
Deep experience building accessible, responsive React/Next.js interfaces in production
Strong CSS fundamentals and familiarity with utility-first frameworks like Tailwind
Experience working with modern component systems such as ShadCN or similar design systems
Comfortable building and integrating backend APIs (bonus if you've worked with HonoJS or lightweight frameworks)
Proficient with relational databases such as Postgres, and how to extend schemas to support new features
Familiarity with testing practices and tools like Vitest (or similar testing frameworks)
Experience integrating analytics tools and using product metrics to guide iteration
Clear communicator and strong collaborator across design, product, and engineering teams
Bonus: Experience building real-time or AI-driven UIs, or shipping features for technical audiences
Our Tech Stack:
NextJS
Tailwind
ShadCN
HonoJS
Postgres
Vitest
What we offer:
210k - 231k + equity. Actual compensation will depend on job-related knowledge, skills, experience, and candidate location.
Competitive salary and meaningful equity
Comprehensive healthcare coverage (medical, dental, vision)
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.
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