Senior Full Stack Engineer

About HiO

HiO is an AI Business Partner for small and medium business owners, unifying customer conversations from every platform into a single, intelligent co-worker that proactively surfaces growth opportunities and flags what actually needs the owner’s attention. 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.
• Bonus: Experience with AI/LLM integrations, WebSockets, or customer service platforms.

Why HiO

• High Impact: Be a foundational member of a core engineering team, playing a pivotal role in redefining how small businesses engage with their customers.
• Cutting-Edge Tech: Build at the forefront of agentic AI, solving first-of-its-kind challenges at the intersection of backend orchestration and human collaboration.
• Growth & Equity: Competitive compensation, meaningful equity, and real career growth in a fast-scaling, VC-backed AI startup.