Founding Product Engineer

About the Role Join an early-stage consumer AI company as its founding product engineer, owning the agent and the end-to-end user experience. You will shape how the assistant makes decisions, communicates, and takes action, while working hands-on across product engineering, prompts, and evaluation systems. What You'll Do Build the agent decision-making layer, including tool-calling loops, memory, context assembly, prompt engineering, and model routing. Create evaluation infrastructure with conversation replay, turn-level judging, and regression suites to guide release decisions. Own mobile and web product experiences, from onboarding and first interactions through ongoing use, group conversations, approvals, and trusted connections. Ship features end to end, using experimentation and feature flags to measure their impact. Develop integrations with email, calendars, bookings, payments, and browser automation, including OAuth and spending approval flows. Review conversations and speak with users regularly to inform product decisions. Establish engineering standards and help grow the team. What We're Looking For At least 4 years of software engineering experience, including work at an AI product company, AI lab, or consumer product company. Production experience building agents with tool use, long-running conversations, and memory, along with evaluation systems used to inform shipping decisions. Full-stack experience with TypeScript, React, Next.js, and PostgreSQL. Experience with third-party APIs, OAuth, payments, or LLM agent tooling such as function calling, MCP servers, or browser automation. A record of owning features end to end and delivering measurable product impact, with strong product and design judgment. Comfort using AI-assisted development workflows while verifying and taking ownership of shipped code. Post-training or fine-tuning experience is a plus. Compensation & Benefits Salary range: $200,000 to $300,000 USD annually. Visa sponsorship is not available. Location On-site in San Francisco, California, United States.