Description:

LMArena is seeking an experienced Senior Frontend Product Engineer to lead the design and development of intuitive, AI-focused user experiences across their platform.
The engineer will 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.
The 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 include leading the development of UI and application logic for the chat interface using React and Next.js, crafting intuitive and responsive user experiences, collaborating with design to maintain a cohesive visual language, implementing accessibility standards and internationalization support, expanding backend data structures, planning and integrating analytics, visualizing feature performance, and owning the full feature lifecycle.

Requirements:

Candidates must have 5+ years of experience in software engineering, focusing on full-stack or frontend product development.
Deep experience in building accessible, responsive React/Next.js interfaces in production is required.
Strong CSS fundamentals and familiarity with utility-first frameworks like Tailwind are necessary.
Experience with modern component systems such as ShadCN or similar design systems is expected.
Candidates should be comfortable building and integrating backend APIs, with a bonus for experience with HonoJS or lightweight frameworks.
Proficiency with relational databases such as Postgres and the ability to extend schemas to support new features is required.
Familiarity with testing practices and tools like Vitest or similar testing frameworks is necessary.
Experience integrating analytics tools and using product metrics to guide iteration is expected.
Clear communication and strong collaboration skills across design, product, and engineering teams are essential.
Bonus points for experience building real-time or AI-driven UIs, or shipping features for technical audiences.

The position offers a salary range of $210k - $231k plus equity, with actual compensation depending on job-related knowledge, skills, experience, and candidate location.
Competitive salary and meaningful equity are provided.
Comprehensive healthcare coverage, including medical, dental, and vision, is included.
The opportunity to work on cutting-edge AI with a small, mission-driven team is available.
The company culture values transparency, trust, and community impact.