Senior Frontend Engineer

Senior Frontend Engineer Build real-time dashboards and AI tools in React and TypeScript, shape frontend direction, and ship customer-focused products with a small, high-impact team. Here’s a more aggressive, YC-style, high-signal, 996-transparent version while keeping it professional and not legally risky: Senior Frontend Engineer Company: Confidential AI Infrastructure Startup Location: Redwood City, California (Onsite, 5 days/week) Compensation: $200,000 - $300,000 Base + Meaningful Equity Visa Sponsorship: Available (H-1B, TN, L-1, E-3, F-1 OPT/CPT, O-1) About the Company We are a high-growth AI infrastructure startup building real-time voice agent systems that power customer support, sales, and operations for modern businesses. We are backed by top-tier venture capital firms and leading angel investors. The company has scaled rapidly from early revenue to tens of millions in ARR in a short time, with a small, highly technical team operating at extreme efficiency. This is a builder-first environment . We care about speed, ownership, and output—not process. Engineers here are expected to think like founders, move fast, and ship continuously. The Opportunity We are hiring a Senior Frontend Engineer to own and scale the customer-facing surface area of our AI platform. This is a high-ownership, high-impact role . You will be responsible for building and evolving the core frontend systems that customers interact with daily—dashboards, real-time interfaces, prompt tooling, and AI workflow products. You will work directly with founders and customers, and your work will ship to production quickly and frequently. If you want slow-moving enterprise processes, this is not the role. If you want to build fast, own deeply, and see your work in production immediately, this is. Responsibilities Own and ship production React applications end-to-end. Build and scale frontend architecture using React + TypeScript. Design and implement real-time dashboards, analytics systems, and AI tooling interfaces. Work directly with backend engineers to integrate APIs and ship features fast. Talk to customers, understand pain points, and turn feedback into shipped product. Make architectural decisions and own frontend technical direction. Write clean, high-performance, production-grade code. Maintain high engineering velocity while keeping code quality high. Participate in rapid iteration cycles and frequent releases. Required Qualifications 3–7 years of frontend engineering experience in production environments. Expert-level React + TypeScript skills. Proven experience building complex, data-heavy web applications. Strong understanding of frontend architecture, performance, and state management. Experience working closely with backend systems and APIs. Ability to operate in high-speed, high-ambiguity environments. Bachelor’s or Master’s in Computer Science or equivalent technical background. Comfortable working onsite in Redwood City, 5 days/week. Preferred Qualifications Experience at high-growth startups or top-tier product companies. Experience building SaaS or developer-facing products. Strong product intuition and customer empathy. Experience working directly with founders or very small teams. Full-stack exposure (Node.js or similar). Tech Stack React TypeScript Node.js Modern JavaScript (ES6+) REST APIs Cloud infrastructure Git Compensation & Benefits $200,000–$300,000 base salary Meaningful early-stage equity Full medical, dental, and vision coverage $70/day meal allowance $200/month wellness reimbursement Visa sponsorship available Direct access to founders and core product decisions Work Style & Expectations This is a high-intensity, high-velocity startup environment . We operate with a bias toward speed, ownership, and execution over process . Engineers are expected to move quickly, ship frequently, and take full responsibility for their areas. During critical product cycles, launches, or customer-driven deadlines, work intensity may increase significantly. While we do not enforce a formal 996 policy, candidates should be comfortable with startup-style intensity, including extended hours when needed to hit company goals . We are explicit about this: This is not a 9–5 role. It is a builder role in a company where speed matters. Interview Process Intro Call Technical Screen (React) Deep Technical + System Design Final Onsite If you want, I can also make a “YC Work at a Startup” ultra-condensed version or a more subtle version that still signals intensity without scaring Big Tech candidates . Locations United States Job location San Francisco Workplace & Culture at Sperton At Sperton, we believe that great results come from great people. Our culture is built on trust, collaboration, and a shared passion for delivering quality in everything we do. We are a Norwegian-owned international company with colleagues across Europe, Asia, and the USA , working together seamlessly across time zones and cultures. Our teams are diverse, yet united by the same goal — to connect people and companies in meaningful ways. We value openness, initiative, and continuous learning. Everyone at Sperton is encouraged to take ownership, share ideas, and challenge existing ways of working to make our solutions even better. Even though we operate globally, our approach is personal. We take pride in creating a supportive and inclusive environment where people feel heard, respected, and motivated to grow — both professionally and personally.