Founding Product Engineer

ABOUT THE ROLE This is a founding-level product engineering role at an early-stage B2B SaaS startup building an AI-driven pricing and monetization platform. You will own product modules end-to-end, work directly with customers and leadership, and help define the architecture and engineering culture of a small, high-output team. Financial fidelity and agentic AI systems are core to what gets built here. WHAT YOU'LL DO - Scope, design, build, and iterate on entire product modules in close collaboration with customers. - Design and evolve architecture for agentic AI systems spanning conversational interfaces, web, terminal UIs, and vendor integrations. - Ensure features are drivable by LLM agents through MCP-style server endpoints and conversational interfaces. - Move pricing and business logic off the client into backend services to preserve financial correctness. - Extend and maintain a typed pricing ontology using Pydantic models covering SKUs, propositions, personas, pricing structures, and more. - Lead architectural reviews and set standards for testing, observability, deployment, and performance monitoring. - Mentor peers, shape product strategy, and help establish engineering culture and best practices. - Treat money-handling code as load-bearing and prioritize root-cause analysis for production issues. - Operate within an AI-native SDLC where agents assist with code generation and automated review gates. WHAT WE'RE LOOKING FOR - 8+ years of software engineering experience with demonstrated ownership of full 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 range: ability to design versioned APIs and ship clean React and TypeScript UIs independently. - Track record of taking ambiguous customer problems to shipped features without a dedicated PM. - Experience with B2B SaaS monetization concepts: pricing models, packaging, quoting, or CPQ. - Experience building or integrating LLM-driven features, agent workflows, or MCP-like tooling servers. - High standards for correctness, especially around financial logic. - Prior experience as an early employee or technical founder who shipped a 0-to-1 B2B product is a strong plus. - Familiarity with SOC 2, GDPR, or data residency constraints is a plus. - Must be authorized to work in the United States; visa sponsorship is not available. COMPENSATION & BENEFITS Base salary: $200,000 to $250,000 USD annually. No visa sponsorship is available. LOCATION On-site in San Francisco, CA. Candidates must be based there or willing to relocate.