Senior Founding Engineer - AI Start-up - NYC

Senior Founding Engineer | Build Agentic AI That Grows Consumer Brands | NYC Start-UpThe Opportunity This is engineer #2 at a start-up backed by a top-tier Silicon Valley VC, building an AI platform that runs the growth operations of consumer brands end to end.The company is doubling its customer base every month, and you'll be the senior engineer who builds the systems behind that growth.You'll be a player-coach, shipping hands-on every day while setting the engineering culture and architecture and mentoring a talented early-career founding engineer.What You'll DoBuild the data infrastructure that tracks every event in each merchant's lifecycle, so the platform learns which actions lead to which outcomesDevelop an agentic, self-optimising growth loop that assesses a merchant's growth operations, identifies what needs to change and executes it automaticallyOwn the full-stack engineering behind the growth engine end to end, with a heavy backend and infrastructure focusShip reliable integrations with Shopify, Meta and TikTok, plus the orchestration tooling around themMentor the founding engineer while staying hands-on-keys every dayAbout You You have 3+ years of full-stack engineering experience (ideally 5–8) with a strong backend emphasis: data infrastructure, event systems and API integrations. You've built agentic or LLM-powered systems in production, integrated them with third-party APIs, and owned them end to end.You've worked at a high-growth tech company or well-funded start-up, or you come from a top engineering programme.You've mentored or led at least one or two engineers, whether as a tech lead, a founder or informally.You're comfortable juggling priorities and creating structure where there isn't any.The team is language-agnostic; the current stack includes Python, TypeScript, LLMs, Shopify, Meta and TikTok Ads APIs, and Klaviyo.Founding-engineer or 0→1 experience and commerce or martech API experience are a bonus.Why Join?Join as engineer #2, with 1%+ equityReport directly to the CEO and shape the architecture, culture and engineering team from day oneWork on real agentic AI: systems that take actions for brands, not a chatbot wrapperGrow with a company doubling its customer base every month, with top-tier investors behind itThe Company You'll be joining an early-stage, VC-backed AI start-up in New York with a small, fast-moving team and a culture built around ownership, speed and building rather than managing.Location New York City, hybrid: 4 days a week in the office. Open to candidates relocating to NYC, and to visa transfers (e.g. OPT, H1B transfer).Compensation $175,000–$225,000 + 1%+ equityLocation New York City, hybrid: 4 days a week in the officeIf you're a hands-on engineer who wants to build agentic systems that grow real businesses, and help shape a company from the ground up, we'd love to hear from you.