Founding Design Engineer

About the Role This is the founding design engineering seat at a seed-stage AI pricing SaaS startup, meaning you will own the entire frontend design system from day one. The team ships UI quickly with the help of AI coding agents, and your job is to make sure everything that lands, whether human-written or agent-written, feels like one coherent product. You are the sole bar-raiser for frontend UX across the company. What You'll Do Define and maintain the design token system, component library, and Tailwind conventions applied across the full product suite. Build and own a shadcn/ui-based component library in production, ensuring it scales as the team grows. Enforce WCAG accessibility standards and translate brand guidelines directly into code. Set patterns for React Query, React Hook Form, and Zod so that agent-generated pull requests land consistently by default. Audit and own frontend tooling: Biome configuration, Playwright end-to-end coverage, and frontend performance. Integrate AI coding tools (such as Claude Code or Cursor) into frontend workflows and establish guardrails for agent-written UI contributions. Design and ship conversational and streaming AI interface patterns for B2B end-users. What We're Looking For 5 or more years building polished product interfaces, with a portfolio of shipped features to show for it. Hands-on ownership of a design system or component library in production as the primary owner, demonstrable via a public repo, portfolio, or detailed walkthrough. Deep expertise in React, strict TypeScript, Tailwind CSS, and component primitives such as shadcn/ui and Radix UI. Experience translating design intent into design tokens, component abstractions, and lint rules. Proven use of AI coding tools in a production frontend environment. Comfort operating as the sole frontend design authority at a fast-moving startup. Nice to have: experience building non-standard AI interfaces (streaming responses, generative views), conversational UI for B2B users, Slack Block Kit or Microsoft Teams Adaptive Cards, or animation libraries such as Framer Motion. Must be authorized to work in the United States; visa sponsorship is not available. Compensation & Benefits Salary range: $180,000 to $220,000 USD annually . Visa sponsorship is not available. Location On-site in San Francisco, California .