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 entire product modules end-to-end, working directly with customers and leadership to shape architecture, ship production-quality systems, and ensure every feature is drivable by LLM agents. On a small team, your technical judgment and customer-facing scope will have an outsized impact.

Location: On-site in San Francisco, CA. Candidates must be based in San Francisco or willing and able to relocate.

Responsibilities

• Scope, design, build, and iterate on whole product modules, from versioned APIs to React UI, in close collaboration with customers.
• Design and evolve architecture for agentic AI systems across Slack bots, terminal interfaces, web, and vendor integrations.
• Ensure features are drivable by LLM agents via MCP/FastMCP servers and conversational interfaces.
• Move pricing and business logic from the client into backend services to preserve financial fidelity.
• Extend and maintain a typed pricing ontology using Pydantic models covering entities such as SKU, Proposition, Persona, Pricing, Customer, Contract, and Quote.
• 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, influence product strategy, and help define engineering culture and best practices.
• Treat money-handling code as load-bearing infrastructure and prioritize thorough root-cause analysis for production issues.
• Adopt and improve an AI-native SDLC where agents assist with code generation and automated review gates.

Requirements

Required:

• 8+ years of software engineering experience with proven ownership of 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: strong backend depth plus the ability to ship clean, independent React and TypeScript UIs.
• Track record of taking ambiguous customer problems all the way to shipped features without a dedicated PM.
• Experience with B2B SaaS monetization concepts: pricing models, packaging, quoting, billing, or CPQ.
• Experience building or integrating AI-assisted features and agent-driven workflows, such as LLM-driven interfaces or MCP-like endpoints.
• High standards for correctness, especially around financial logic and data integrity.
• Must be authorized to work in the United States; visa sponsorship is not available.

Nice to have:

• Built MCP servers or tooling for LLM agents.
• Experience with billing, CPQ, metering, or pricing systems.
• Familiarity with data residency, SOC 2, or GDPR-compliant development practices.
• Prior experience as a technical founder or early employee who shipped a 0-to-1 B2B product to paying customers.

Pay

Salary range: $200,000 to $250,000 USD annually.