Founding Engineer (Backend)

Location: San Francisco, CA (On-site, 5 days/week) Role We're looking for a backend-leaning Founding Engineer (0–7 years experience) who has shipped production software at a pedigreed company — FAANG, high-growth VC- backed startups (Series A+), or equivalent. You'll own projects end-to-end in a fast- moving, early-stage environment and help shape the core infrastructure that AI agents use to communicate and operate in the real world. What You'll Do • Build and design APIs and backend infrastructure that AI agents use to communicate, authenticate, and operate • Own 0→1 projects end-to-end — from scoping customer requirements through system design to production rollout (e.g., IMAP integration, usage-based pricing systems) • Work across the full stack (~80% backend, ~20% frontend/other), touching distributed systems, databases, and developer tooling Proactively pitch ideas — you're expected to bring product and growth thinking, not just execute tickets • Be a frontline point of contact for customer feedback and support enterprise deployments • Write clear, maintainable code and documentation while processing hundreds of thousands of emails per day What We're Looking For • Strong proficiency in TypeScript or modern equivalent frameworks • Experience at a FAANG or well-known VC-backed startup (Series A+) • Deep backend fundamentals: REST API design, system design, server-side architecture • Track record of shipping and owning features from 0→1 in production with real users • CS or technical degree from a top engineering school (especially for new grads) • High agency — you bring ideas and drive execution without needing scope handed to you • Strong communicator of tradeoffs, blockers, and technical decisions • Must be based in or willing to relocate to San Francisco (on-site 5 days/week) Bonus Points • Experience with email, messaging, or protocol-heavy systems (SMTP, IMAP, OAuth) • Exposure to cloud infrastructure, distributed systems, or developer tooling — especially in AI/LLM or agent workflows • Prior founding, fellowship, or 0-to-1 building experience • Evidence of doing hard things outside of engineering — competitive athletics, self-directed projects, anything showing grit and agency