Senior Frontend Engineer (Founding Team) | San Francisco

About the Company Our client is a San Francisco-based AI-native startup building a new generation of intelligent systems for knowledge workers. Their product is designed to go beyond traditional AI tools — it understands user context, prioritizes workflows, and proactively supports decision-making , acting as a true collaborator rather than a reactive assistant. Backed by leading investors and built by former founders and senior operators, the company is focused on redefining how humans interact with AI in daily work.

Location: San Francisco, CA (On-site) Employment Type: Full-time Salary: $180,000 – $240,000 + Equity Role Overview This is a foundational frontend engineering role with full ownership of the product's user interface. The position involves designing and building high-performance, intuitive, and scalable frontend systems for a complex AI-driven application. The role requires strong product thinking, as many features will be defined and executed without detailed specifications.

Key Responsibilities Own and develop the frontend architecture end-to-end Build responsive, high-performance, and user-centric interfaces Translate product ideas into functional and intuitive user experiences Make independent product and design decisions in an ambiguous environment Optimize performance, data flow, and real-time interactions Collaborate closely with founders and engineering team on product direction Requirements 4+ years of experience in Frontend Engineering Strong expertise in React and TypeScript Proven experience building complex, production-level web applications Deep understanding of state management and performance optimization Ability to work across the stack when needed Strong product mindset and design intuition Preferred Qualifications Experience with real-time systems (e.g., CRDTs, multiplayer apps) Experience building interfaces for AI / LLM-based products Familiarity with local-first architectures (IndexedDB, service workers) Previous experience as an early-stage or founding engineer Strong visual or UX sensibility Work Environment & Requirements Fully on-site role in San Francisco (5 days/week) Candidates must be based in the Bay Area or willing to relocate prior to start US work authorization required or eligibility for O-1 visa What We Offer Ownership of frontend for a category-defining AI product Direct collaboration with experienced founders and high-performing team Fast-paced, high-impact environment with real product influence Competitive compensation with meaningful equity upside If you're motivated by ownership, product impact, and building high-quality systems at speed, this role offers the opportunity to shape a product from the ground up — we encourage you to apply...