Onsite NYC Full-Stack AI Engineer: Zero-to-One Builder

\We are partnering with an early-stage, cutting-edge AI startup in New York City to hire a Full Stack AI Engineer with strong zero-to-one product-building experience. This is a fully onsite position. Candidates must currently live within commuting distance of New York City and be able to work from the company’s Manhattan office five days per week. Please do not apply if you are seeking remote or hybrid work. About the Role Our client is looking for a highly hands-on engineer who can help build and launch AI-native products from the ground up. You will work closely with the founders to turn ideas into production-ready applications and help shape the company’s technical foundation. The right candidate is comfortable working across frontend, backend, infrastructure, and AI systems. You should enjoy fast-moving startup environments, changing requirements, rapid iteration, and taking complete ownership of what you build. Responsibilities Build, test, launch, and improve full-stack products from zero to one Develop modern frontend applications using React, Next.js, or similar technologies Build backend services, APIs, databases, and third-party integrations Create AI-powered features using large language models and multimodal models Build AI agents that can use tools, complete workflows, and interact with external systems Develop retrieval-augmented generation, embeddings, vector search, and knowledge systems Integrate voice AI, speech-to-text, text-to-speech, or real-time conversational systems Implement structured outputs, tool calling, model routing, and human approval workflows Build evaluation, monitoring, and testing systems for AI performance Improve application reliability, scalability, security, latency, and AI inference costs Work directly with founders, users, and product stakeholders Help make product, architecture, and technology decisions Qualifications 4 or more years of professional software engineering experience Proven experience building and launching a product from zero to one Prior experience working at an early-stage startup Strong experience across frontend and backend development Strong skills in TypeScript, JavaScript, React, and Next.js Backend experience with Node.js, Python, FastAPI, Go, or similar technologies Experience with PostgreSQL, APIs, cloud infrastructure, and production deployments Hands-on experience integrating large language models into production applications Experience with AI agents, RAG, tool calling, embeddings, multimodal AI, or voice AI Strong product judgment and the ability to operate with limited direction Ability to move quickly while maintaining high engineering standards Must be actively hands-on and writing production code Preferred Experience OpenAI, Anthropic, Gemini, or open-source AI models Model Context Protocol and agent orchestration frameworks LangGraph, LlamaIndex, Vercel AI SDK, or similar tools Vector databases such as Pinecone, Qdrant, Weaviate, or pgvector Voice AI, WebSockets, WebRTC, or real-time streaming systems AI evaluations, observability, prompt injection protection, and model security Docker, AWS, Google Cloud, Azure, or serverless infrastructure Experience as an early, founding, or first engineering hire Ideal Candidate You are a builder who prefers creating new products over maintaining mature systems. You are comfortable wearing multiple hats, making decisions quickly, and turning incomplete ideas into products customers can use. You understand that strong AI products require more than connecting an application to a model API. You know how to build dependable workflows, evaluate output quality, manage latency and cost, and create safeguards around AI-generated actions. Candidates whose experience is exclusively with FAANG companies, large enterprises, or mature technology organizations will not be considered. FAANG experience is welcome when combined with meaningful early-stage startup and zero-to-one product experience. Location Requirement This position is onsite in Manhattan five days per week. Candidates must already live within a reasonable commuting distance of New York City. Remote, hybrid, relocation-dependent, and out-of-area candidates will not be considered. #J-18808-Ljbffr Top Echelon