Full Stack Engineer

About HiO HiO is an AI Business Partner for small and medium business owners, learning how each business operates through its customer interactions, existing tools, and workflows. Our AI proactively identifies growth opportunities and helps business owners take action to move their business forward. The market demand for this kind of intelligent automation is explosive, but executing it flawlessly is a deep technical challenge. We aren't just building a simple LLM wrapper; we are architecting a complex, highly reliable system capable of orchestrating sophisticated agentic workflows at scale. To meet this massive market pull, we’ve raised a $16M seed round from the visionary VCs behind OpenAI and Anthropic, alongside Wix as a strategic investor. We’re a high-talent, fast-moving team building the future of how small businesses thrive, and we’re just getting started. About the Role Join HiO as a Senior Full Stack Engineer and help architect our Agentic AI System. You’ll be responsible for building the entire lifecycle of our product—from high-performance Node.js services on AWS to polished, real-time React experiences that make AI feel human. In this role, you will bridge the gap between complex AI logic and intuitive user interfaces. You’ll have a seat at the table to influence our technical foundation, backend architecture, and product direction as we scale AI-native customer experiences to millions of SMBs. What you’ll do End-to-End Ownership: Build and maintain scalable, performant web and mobile applications using React, TypeScript, and Node.js . Architect for Scale: Design and implement robust backend services and APIs on AWS to support real-time, agent-driven features. AI Integration: Collaborate with AI engineers to integrate sophisticated LLM orchestrations and live customer interactions into a seamless product experience. Foundation Building: Shape the architecture, standards, and CI/CD pipelines of HiO’s full-stack systems. Product Craftsmanship: Partner with product and design to craft highly polished, intuitive, and delightful user experiences from the database to the UI. Technical Leadership: Champion best practices in system design, performance, security, and code quality. What we’re looking for 6+ years of experience building and scaling modern web applications in a Full Stack capacity. Frontend Mastery: Deep expertise in React and TypeScript, with a strong eye for design and UX detail. Backend Excellence: Proven experience building production-grade services with Node.js. Cloud Native: Strong hands-on experience with AWS infrastructure (Serverless, Lambda, ECS, etc.). System Thinker: Experience with real-time, data-intensive interfaces and complex state management. Startup Mindset: Comfortable in a fast-paced, product-led environment where you need to move fast without breaking things. Nice to Have Experience building AI-powered products, including LLM integrations or agent-driven features. Experience working in AI-native companies where AI is at the core of the product. Previous experience working in early-stage startups and small, fast-moving teams. Experience building B2B SaaS products for small and medium-sized businesses (SMBs). Why HiO High Impact: Be a foundational member of a core engineering team, playing a pivotal role in transforming how small businesses identify growth opportunities and take action. Cutting-Edge Tech: Build at the forefront of agentic AI, solving first-of-its-kind challenges at the intersection of AI and human collaboration. Growth & Equity: Competitive compensation, meaningful equity, and real career growth in a fast-scaling, VC-backed AI startup. Mission: Make a real impact by helping small and medium-sized businesses unlock their growth potential through AI.