Senior Backend 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. 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

As a Senior Backend Engineer, you will play a pivotal role in scaling and evolving the core systems that power HiO's agentic AI platform. With a product already live in production, you will work closely with our engineering leadership to take our infrastructure to the next level- from real-time orchestration and automation logic to scalable APIs and data pipelines.

You'll work at the heart of our stack, combining Node.js and Python to build high-performance, reliable backend services that power our voice and digital agents, analytics, and AI integrations. This is a hands-on role for a highly self-sufficient builder who loves elegant systems, clean code, and moving fast without breaking things.

What You'll Do

• Drive Execution: Act autonomously to define your own technical tasks, prioritize effectively, and push features to the finish line while collaborating seamlessly with a tight-knit core team.
• Build & Scale: Collaborate on system architecture and build out scalable backend services in Node.js and Python for our growing production workloads.
• Orchestrate AI: Integrate large language models (LLMs) and build multi-step, reasoning-based AI agent workflows using frameworks like LangGraph (a strong plus).
• Enhance Infrastructure: Own backend performance, observability, and infrastructure scalability, optimizing services in a cloud-native environment (AWS / GCP).
• Cross-Functional Collaboration: Work closely with frontend, AI, and product teams to design and implement impactful cross-functional features.
• Data & Delivery: Manage databases, caching, and distributed systems with strong data modeling practices, while upholding rigorous engineering standards and CI/CD practices.

What We're Looking For

• Experience: 7+ years of backend engineering experience building and scaling production-grade systems.
• Startup DNA: Previous experience as a founding engineer or a proven track record of thriving in a small, early-stage startup environment is a huge plus.
• Extreme Ownership: You are fiercely self-reliant. You don't wait for a ticket to be perfectly scoped; you can navigate ambiguity, define the work that needs to be done, and execute.
• Technical Deep Expertise: Deep knowledge of Node.js and Python, with a solid understanding of async and concurrency.
• Cloud & Architecture: Proven experience with cloud platforms (AWS, GCP) and managing microservices-based architectures with real production workloads.
• Database Mastery: Strong knowledge of databases (SQL + NoSQL), caching, and distributed architectures.
• AI Familiarity: Experience with LLM integration, LangGraph, or other agent orchestration frameworks is a strong plus.
• Education: BSc in Computer Science, Software Engineering, or equivalent.

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 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 tangible impact by bringing AI superpowers to millions of small businesses worldwide.