Founding Product Engineer

ABOUT THE ROLE This is a founding product engineering role at an early-stage B2B SaaS startup building an AI-driven pricing and monetization platform. You will own entire product modules end-to-end, working directly with customers and leadership to shape architecture, ship production-quality systems, and ensure every feature is operable by LLM agents. On a small team, your technical and product judgment will directly define what gets built and how. WHAT YOU'LL DO - Scope, design, build, and iterate on whole product modules, from versioned API to React UI, in direct collaboration with customers. - Design and evolve architecture for agentic AI systems across conversational interfaces, web, and vendor integrations. - Ensure features are drivable by LLM agents via MCP/FastMCP servers and conversational interfaces. - Move pricing and business logic off the client into backend services to preserve financial fidelity. - Extend and maintain a typed pricing ontology using Pydantic models covering SKUs, propositions, personas, pricing, and more. - Lead architectural reviews and technical discussions to keep systems robust, extensible, and secure. - Establish testing, observability, deployment, and performance monitoring practices for AI-driven features. - Mentor peers, shape engineering culture, and contribute to product strategy. - Treat money-handling code as load-bearing infrastructure, with rigorous root-cause analysis for production issues. - Adopt and improve an AI-native software development lifecycle where agents assist with code and automated review gates. WHAT WE'RE LOOKING FOR - 8 or more years of software engineering experience, with demonstrated ownership of entire product areas at startup or staff-level scope. - Deep backend expertise with production experience in FastAPI, Python, and MongoDB or a comparable stack. - Credible full-stack skills: able to ship a clean, data-dense React and TypeScript UI independently. - Track record of taking ambiguous customer problems to shipped features without a dedicated product manager. - Experience with B2B SaaS monetization concepts: pricing models, packaging, quoting, billing, or CPQ. - Experience building or integrating AI-assisted features and agent-driven workflows, including LLM interfaces and MCP-style endpoints. - High standards for correctness, especially around financial logic and money-handling code. - Familiarity with data residency, SOC 2, or GDPR constraints is a plus. - Prior experience as a technical founder, co-founder, or early employee who shipped a 0-to-1 B2B product to paying customers is a plus. - US work authorization required; visa sponsorship is not available. COMPENSATION & BENEFITS The base salary range is $200,000 to $250,000 USD annually. Visa sponsorship is not available. LOCATION This role is fully on-site in San Francisco, CA. Candidates must be based in San Francisco or willing to relocate.