Senior Python Backend Engineer

Senior Python Backend Engineer - Startup – San Francisco Bay Area Visa sponsorship not available, US Citizens only. Please do not apply if you are seeking sponsorshiSenior Python Backend Engineer is required by a AI startup building AI customer-service agents that can talk to customers by phone, chat, or messaging apps almost like a human support representative. The company is looking for a senior python engineer to help shape the technical direction of their backend systems. You'll lead complex projects, make architectural decisions that affect the whole platform, and raise the bar for engineering quality across the team. This is a role for someone who wants to build, not just advise. You'll write code, own systems, and ship, but you'll also be expected to think beyond your immediate work to identify what the team should be building next and how we should build it.Requirements STEM degree from a top university globally7 - 15 years of experience in backend/infrastructure engineering, with Python and distributed systemsSystem design expertise for scalable, reliable backend platformsExperience at high-growth SaaS startups or top-tier techExperience independently owning and driving initiatives to completion without oversightUses AI coding tools (Curs or Claude) activelyMust work on-site 5 days/week in San Francisco. Must also already be located locally, not interested in candidates who need to relocate.What you'll do: Designing how our agent infrastructure should evolve as we scale, making tradeoffs between speed, reliability, and complexityOwning the most ambiguous, highest-stakes projects where getting it wrong would hurt the businessIdentifying gaps in our systems before they become problems and building the case for addressing themSetting standards for code review, system design, and operational excellence through your own workTech stackPython, Django, FastAPI, TypeScript, Node.js, AWS, Modal, Kubernetes, Postgres, Next.js