Founding Frontend Engineer

Founding Frontend Engineer Location: San Francisco, CA — 5 days per week in-office Compensation: $180,000–$235,000 base + 0.10%–1.25% equity The Opportunity I'm representing a well-funded, early-stage AI company in San Francisco that is building technology focused on making AI genuinely capable at creative work, starting with UI and product design. They're a deliberately small team of just eight people and are now looking for a Founding Frontend Engineer to take significant ownership of the frontend and help shape the product from an early stage. This isn't a role where you'll simply pick up tickets or translate finished Figma designs into React components.They're looking for someone who can take an ambiguous product problem, think through the interaction and UX, make strong technical decisions and build the solution through to production.You'll work directly with the founders and have significant influence over how the product looks, feels and behaves. What You'll Be Doing You'll own complex, highly interactive frontend experiences at the intersection of AI, design and software development. You'll be responsible for: Building and owning core product experiences using React, Next.js and TypeScriptArchitecting frontend systems from first principlesBuilding sophisticated, responsive and highly interactive user interfacesSolving challenging browser-level performance and rendering problemsWorking with the DOM and modern browser APIsMaking product and UX decisions without requiring detailed design specificationsTaking features from an ambiguous idea through architecture, implementation and productionWorking directly with the founders to help shape product directionHelping establish frontend engineering standards as the company grows You'll ideally have: Exceptional production experience with React and Next.jsStrong TypeScript and modern JavaScript fundamentalsDeep understanding of browser internals, the DOM, rendering/paint behaviour, event loops, memory and frontend performanceExperience solving genuinely difficult browser and frontend performance problemsStrong frontend architecture and system-design abilityA track record of building technically complex, polished product interfacesStrong product and design instincts, with the ability to make good UI/UX decisions without relying heavily on a designerExperience owning substantial frontend products or systems end-to-endThe ability to operate independently in an ambiguous, fast-moving environmentComputer Science degree or equivalent technical background Backgrounds That Could Be Particularly Relevant Design-led product companies You've built products where exceptional UI, interaction and design quality are fundamental to the user experience. Early-stage / founding teams You've joined a strong startup early and personally owned substantial parts of the frontend from 0→1. High-bar engineering environments You've worked alongside exceptional engineers on technically demanding products where engineering quality is taken seriously. You Could Be a Great Fit If... You've built products where the frontend itself was technically difficult.That could include complex interactive interfaces, browser-intensive applications, creative/design tools, real-time products, sophisticated editors, data visualisation, rendering systems or frontend infrastructure.You understand why an application behaves the way it does in the browser, rather than simply knowing which React optimisation to apply.You're also comfortable moving between frontend architecture, browser behaviour, product thinking and UI/UX. If you're a frontend engineer who has gone deep rather than broad, enjoys technically difficult UI problems and wants genuine ownership of an early-stage product, I'd be keen to speak with you.