Staff Backend Engineer

About Circuit Circuit is the AI execution layer for the physical economy. Industrial and manufacturing enterprises run on expertise: the hard-won knowledge of how complex products are engineered, configured, sold, and supported. That expertise is scarce, slow to transfer, and walking out the door as a generation of experts retires. It lives in PDFs, spreadsheets, and the heads of a few people, and the hardest technical decisions wait on whoever happens to know. Circuit puts expert judgment in everyone's hands. We capture how the best people make critical technical decisions and turn it into agents that do the judgment-heavy work, so anyone, regardless of skill level, can make the right call, from quote to install and support, with the accuracy these environments demand. Circuit is built by operators. Our leadership team has built and scaled real industrial companies, and we are already live in production with category-leading manufacturers. We are not bolting AI onto an old playbook. We are building the layer that runs the last mile of how the physical economy executes. The Role As a Staff Backend Engineer, you'll play a critical role in shaping and scaling Circuit's backend systems and infrastructure. You'll own complex backend services built primarily in Go and Python, with a focus on resilience, scalability, and performance under increasing load. A defining challenge of this team is data scale. As Circuit goes deeper with enterprise customers, the data in our indexes grows dramatically — driving new architectural demands around database sharding, self-hosted storage, efficient embedding indexes, and safe, high-stakes data migrations. Solving these problems is what unlocks continued product velocity for the entire backend team. Beyond the data platform, a significant portion of Circuit's agentic functionality lives in the backend, and you'll be instrumental in ensuring it can evolve and handle new levels of demand. Our teams operate with a high degree of independence and ownership. Engineers are expected to communicate early and clearly to avoid surprises, act with urgency, and fix issues without waiting to be asked. We hold a high bar for quality while shipping frequently, testing assumptions early, and learning quickly from real-world feedback. You'll often work through ambiguity by framing problems, asking the right questions, and making progress with incomplete information. Curiosity and internal drive matter: we expect engineers to deeply understand the systems they build, the customers they serve, and how their work creates real-world impact.