Sr AI Engineer - Bay Area (YC Startup)

We're seeking a Senior AI Engineer to build and scale next-generation AI systems that bring agentic workflows to life. In this role, you'll design and implement LLM-powered pipelines with continuous evaluation and feedback loops, develop organization-specific customization layers, and create engaging voice- and message-based agents. Beyond deep technical execution, you'll collaborate closely with product teams, stakeholders, and users to shape product direction and translate real-world needs into scalable solutions. This is a hands-on, product-focused role for a builder who thrives in ambiguity, adapts quickly to new frameworks, and delivers impactful, enterprise-grade AI solutions at startup speed. Responsibilities • Design and implement agentic workflows powered by LLMs for real-world enterprise use. • Build customization layers tailored to organization-specific logic and requirements. • Collaborate directly with product teams, founders, and users to understand pain points and iterate quickly. • Translate user and product feedback into production-grade technical solutions. • Develop voice-based and message-based learning agents with evaluation loops and continuous monitoring. • Architect AI pipelines (RAG, prompt engineering, evaluation) and reliable infrastructure for complex environments. • Clearly communicate technical decisions to both technical and non-technical stakeholders. • Manage multi-agent orchestration and core AI system infrastructure. Qualifications • 5+ years of experience in machine learning (PyTorch, TensorFlow). • 2+ years hands-on experience with LLMs (Hugging Face, OpenAI, Anthropic). • Proven experience building and deploying production AI systems, including RAG and vector search. • Knowledge of prompt engineering, AI safety, and content filtering best practices. • Familiarity with Rails a plus; strong candidates can ramp quickly. • Experience with REST APIs, PostgreSQL, ActiveRecord, and RSpec. • Understanding of frameworks like LangChain or LlamaIndex, or ability to learn rapidly. • Strong written and verbal communication skills; experience working directly with users or clients. • Startup experience preferred, ideally with products selling to enterprise customers. Ideal Candidate • Innovative Builder: Designs and optimizes sophisticated AI workflows from ideation to deployment. • Product-Minded Communicator: Excels at translating real-world feedback into scalable technical solutions. • Technically Excellent: Strong expertise in production AI systems and infrastructure. • Collaborative & Fast-Moving: Thrives in ambiguity, iterates quickly, and works seamlessly with small, high-impact teams. Location: Bay Area, CA (on-site / hybrid as required) Visa/Relocation: Candidates must already be authorized to work in the U.S. and located in the Bay Area. Apply tot his job