We're hiring a Senior AI Backend Engineer who will own the backend infrastructure behind multimodal AI agents running in real enterprise environments. This is a hands-on role where distributed systems meet applied AI: you'll build the services that take in messy real-world data, orchestrate agent workflows, keep enterprise data secure, and deliver reliable results at scale. You'll own your area end to end from day one. What you'll do • Design, build and deploy backend services end to end, from data ingestion and storage to API design, background processing and deployment • Build AI orchestration pipelines that hold up against real-world variability, using structured outputs, tool calling, state management and guardrails • Define the orchestration patterns and evaluation frameworks the team works from, including evals and regression tests so model changes ship with confidence • Set technical direction for your subsystems: own the roadmap and decide when to pay down tech debt and when to push forward • Build for enterprise security: least-privilege access, tenant isolation, auditability and safe data handling • Work with product, design and frontend engineers to turn loose product ideas into concrete technical plans • Mentor earlier-career engineers through code reviews, architecture guidance and technical writing You may be a fit if • You have 4+ years of designing and shipping production backend systems, with real architectural ownership • You've designed services from scratch that other engineers now build on in production • You've shipped AI-powered features to production and have your own opinions on orchestration patterns, evals and how these systems fail at scale • You're comfortable setting direction and owning a roadmap rather than working from a predefined spec • You're mostly backend (around 80% or more) but happy to work across the stack when needed • You can work from the San Francisco office 4 days a week (Wednesday is flexible) Nice to have • Experience at both large, high-caliber companies and fast-moving startups • A founder or founding engineer background • A degree in CS, math, physics, statistics or another highly technical field • You build with AI tools every day and can help the team move faster with AI-assisted workflows What we offer • Competitive compensation plus equity • Fully covered medical, dental and vision • Visa sponsorship (H-1B, O-1, OPT) and relocation support to the Bay Area • Learning and wellness budgets • Daily catered meals at the office