Senior AI Builder

Replit is the agentic software creation platform that enables anyone to build applications using natural language. With millions of users worldwide, Replit is democratizing software development by removing traditional barriers to application creation. The AI Studio is the team responsible for designing, building, and operationalizing internal software platforms across every functional department of the company, including People Operations, Customer Support, Sales, Marketing, Finance, Recruiting, and Executive Operations. We treat each internal department as its own product surface, and in truth as its own startup, with its own customers, its own metrics, and its own reasons for existing. We ship custom software, built on Replit’s own platform, to solve operational problems that off-the-shelf SaaS tools cannot serve well at our scale and pace of growth. Position Summary The Member of Technical Staff (AI Builder) is a full-time builder role with substantial autonomy. You will design, architect, and ship AI-powered internal platforms that run the operations of the company across many departments at once. This is not a role for someone who wants a narrow, well-defined lane. It is a role for someone who wants to walk into an ambiguous business problem, understand it well enough to argue about it with the department lead, and then ship the software that fixes it. We are looking for people who genuinely understand the mechanics of a business: how revenue is actually made, why recruiting velocity matters, what makes support scale or break, how finance closes a month, and why each department is critical to whether the company wins or loses. You do not need to have run every function, but you need to respect why each one exists and be able to reason about it like an operator, not just an engineer. Because we treat each department as its own startup, we strongly favor people who have either run their own business or worked on a fast-scaling startup. You know what it feels like to build with incomplete information, to ship before it is comfortable, and to own an outcome rather than a ticket. The work is genuinely a ton of fun, and it is also demanding: it rewards diplomacy, creativity, technical depth, and business acumen in roughly equal measure. You will move fast, work long hours when it matters, and switch fluidly between a deep technical conversation and a conversation with a non-technical stakeholder who just needs their problem solved. Key Responsibilities Internal Platform Design and Engineering Design, architect, and ship custom AI-powered internal platforms that serve specific operational needs across Replit’s functional departments, including but not limited to People Operations, Customer Support, Sales, Recruiting, Marketing, Finance, and Executive Operations. Translate ambiguous, often non-technical business requirements into technical specifications, system architectures, and shipped software products. Own platform development end-to-end, including front-end interfaces, back-end services, data models, third-party integrations, and AI model orchestration. Applied AI and Large Language Model Engineering Architect multi-stage AI pipelines incorporating large language models, including prompt engineering, tool-call architecture, structured output generation, retrieval-augmented generation, and agentic workflows. Conduct model selection across multiple frontier and open-source providers, evaluating models against cost per query, latency, output quality, reliability, and task-specific performance. Design and implement evaluation frameworks for AI features, including test datasets, scoring rubrics, and regression tests, so that AI-driven workflows stay reliable in production. Optimize AI systems for cost and performance, including the appropriate use of lighter-weight models for qualification passes, batching strategies for high-throughput workloads, and caching architectures. Business Understanding and Stakeholder Partnership Trea