Founding Fullstack Engineer

Location: San Francisco, CA (Onsite)Compensation: Market competitive base + equityStage: Seed | AI | ~$4M funded | ~5 person teamAbout Our ClientOur client is a seed-stage AI company building the operating system for in-house legal teams. Their platform eliminates the fragmented, manual workflows that cost legal teams millions in outside counsel spend each year, replacing them with centralized, AI-powered matter management and contract workflows.The long-term vision is to become the universal knowledge layer for legal operations. They're early, well-funded, and already running active pilots with major in-house legal teams.Culture: high-ownership, technically rigorous, transparent, and fast-moving. Everyone here builds things that matter and ships them.The RoleThis is a founding-level engineering role. You won't be handed a backlog of tickets. You'll look at a problem, decide how to solve it, build it, and own what happens after it ships.As a Senior Full-Stack Engineer working on the Platform, you'll be responsible for the integrations, data infrastructure, and AI retrieval systems that sit at the core of the product. You'll have a direct line to leadership, real input on roadmap decisions, and the kind of surface area that only exists at a 5-person company.If you want to know you built something, this is that job.What You'll OwnThe integration layer connecting the platform to Google Workspace, Slack, Notion, and future enterprise systems. You'll design the architecture, own the reliability, and extend it as the product grows.Backend services and APIs that power core product workflows. You'll make the calls on structure, performance, and scalability.The AI retrieval and knowledge systems (RAG pipelines, indexing, ETL) that make the platform actually intelligent. You'll understand these well enough to improve them, not just maintain them.Frontend surfaces that legal teams interact with daily. You care about the experience, not just the functionality.Workflow orchestration across complex async processes. You'll architect for correctness and resilience, not just delivery.Observability and platform health. You'll know when something's wrong before a user does.Engineering standards and culture. As one of the earliest engineers, what you build and how you build it sets the bar.What We're Looking For3+ years of professional engineering experience, ideally in a startup or high-velocity environmentStrong full-stack ability: Python/FastAPI on the backend, React/TypeScript on the frontendA track record of owning features end-to-end, not just shipping PRsComfort operating in ambiguity. You don't need a complete spec to start building.Strong system design instincts. You think about what breaks before it breaks.Bonus points for:Temporal.io or comparable workflow orchestration experienceETL pipelines, RAG systems, or LLM API integrations (Anthropic, OpenAI, Gemini)PostgreSQL, Redis, distributed systems at scaleAWS production deploymentsTailwindCSS / shadcn/uiTech StackPython, FastAPI, React, TypeScript, Temporal.io, PostgreSQL, Redis, Docker, AWS, TailwindCSS, shadcn/ui, Anthropic API, Google Gemini APIWhy This RoleGreenfield platform with real traction. You're not inheriting tech debt, you're building the foundation.Direct access to leadership and a real voice in product directionFive-person team. Your fingerprints are on everything.A problem space with genuine complexity: AI, legal workflows, enterprise data, and security intersecting in interesting waysInterview ProcessRecruiter ScreenTechnical Deep DiveIntegration or System Design ExerciseCulture / Values Interview