Founding Product Engineer

About the Role An early-stage AI-native B2B SaaS company building an AI-driven pricing and monetization platform is looking for a Founding Product Engineer to join as one of the first engineers on the team. This is a hands-on, high-ownership role where you will define architecture, own entire product modules end-to-end, and work directly with customers and leadership to shape how the product evolves. The platform helps B2B companies continuously optimize their pricing lifecycle — covering packaging design, scenario simulation, quote recommendations, deal coaching, discount governance, and more. You will be instrumental in moving core financial logic server-side, extending a typed pricing ontology, and ensuring every feature can be driven by LLM agents. This role is on-site in San Francisco, CA. US work authorization is required; visa sponsorship is not available. What You'll Do Own whole product modules end-to-end: scope with customers, design versioned APIs, build the UI, ship, and iterate. Design and evolve architecture for agentic AI systems across Slack bots, terminal UIs, web interfaces, and vendor integrations. Ensure product features are drivable by LLM agents via MCP/FastMCP server endpoints 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 (e.g., SKU, Proposition, Persona, Pricing — with Customer, Contract, and Quote on the roadmap). Lead technical discussions and architectural reviews to keep systems robust, extensible, and secure. Establish testing, observability, deployment, and performance monitoring practices for AI-driven features. Mentor peers, influence product strategy, and help set engineering culture and best practices. Treat money-handling code as load-bearing; prioritize root-cause analysis for production issues. Adopt and continuously improve an AI-native SDLC where agents assist with code generation and automated review gates. What We're Looking For Must-haves: 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 modern stack). Proven track record of shipping end-to-end modules: customer scoping → versioned API design → React UI → production delivery. Credible frontend range with React and TypeScript; able to ship a clean, polished UI independently. Experience designing server-side business logic, versioned APIs, and ensuring testing, observability, and deployment for AI-driven features. Experience building or integrating AI-assisted features and agent-driven workflows (e.g., LLM-driven interfaces, MCP-like endpoints). Familiarity with B2B SaaS monetization concepts: pricing models, packaging, and quoting. High standards for correctness, especially around financial logic. Authorized to work in the United States without visa sponsorship. Nice-to-haves: Experience building MCP servers or tooling for LLM agents. Background in billing, CPQ, metering, or pricing systems. Experience with data-dense frontend components and/or conversational interfaces. Familiarity with data residency, SOC 2, or GDPR-compliant development practices. Prior experience as a technical founder, co-founder, or early employee who shipped a 0-to-1 B2B product to paying customers. Compensation & Benefits Salary: $200,000 – $250,000 USD per year Early-stage equity commensurate with a founding-team role Opportunity to shape product, engineering culture, and company direction from day one Location This is an on-site role based in San Francisco, CA. Candidates must be willing and able to work in person. US work authorization is required; the company does not offer visa sponsorship.