Senior Frontend Engineer (Founding Team) | San Francisco

About The CompanyOur 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-timeSalary: $180,000 – $240,000 + EquityRole OverviewThis 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 ResponsibilitiesOwn and develop the frontend architecture end-to-endBuild responsive, high-performance, and user-centric interfacesTranslate product ideas into functional and intuitive user experiencesMake independent product and design decisions in an ambiguous environmentOptimize performance, data flow, and real-time interactionsCollaborate closely with founders and engineering team on product directionRequirements4+ years of experience in Frontend EngineeringStrong expertise in React and TypeScriptProven experience building complex, production-level web applicationsDeep understanding of state management and performance optimizationAbility to work across the stack when neededStrong product mindset and design intuitionPreferred QualificationsExperience with real-time systems (e.g., CRDTs, multiplayer apps)Experience building interfaces for AI / LLM-based productsFamiliarity with local-first architectures (IndexedDB, service workers)Previous experience as an early-stage or founding engineerStrong visual or UX sensibilityWork Environment & RequirementsFully on-site role in San Francisco (5 days/week)Candidates must be based in the Bay Area or willing to relocate prior to startUS work authorization required or eligibility for O-1 visaWhat We OfferOwnership of frontend for a category-defining AI productDirect collaboration with experienced founders and high-performing teamFast-paced, high-impact environment with real product influenceCompetitive compensation with meaningful equity upsideIf 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.J-18808-Ljbffr