Founding Engineer

ABOUT THE ROLE Join a small, early-stage team building an advertising technology platform. As Founding Engineer, you will own and develop the production recommendation system, with impact across data, machine learning, and real-time ad delivery. WHAT YOU'LL DO - Design and ship a low-latency ad ranking system that selects campaigns and creative for each opportunity while balancing advertiser performance and user experience. - Build data pipelines and feature infrastructure for ongoing model training across signals such as clicks, installs, and conversions. - Model user behavior and context using engagement history, conversational data, and signals such as geography, device, and session activity. - Develop efficient ad-serving infrastructure designed for sub-second latency and cost-conscious operation. - Build generative agents that create playable and video ad variants, and feed their performance back into the recommendation system. WHAT WE'RE LOOKING FOR - Typically 0 to 3 years of experience, with demonstrated ability to own substantial engineering work. - Experience shipping an ML or AI system to production, ideally owning the full path from data pipelines and model training through serving. - Strong backend, data infrastructure, and production serving skills, including experience with systems operating at significant scale. - Ability to reason from first principles and work across infrastructure, classical machine learning, and AI agents. - Experience with recommendation systems, ranking, advertising technology, or consumer products is useful; gaming interest and experience with playable ads are also valued. - PyTorch experience and an active GitHub profile or shipped side projects demonstrating technical work are welcome. - Must be a U.S. citizen or permanent resident and able to work on-site in San Francisco five days per week. COMPENSATION & BENEFITS Base salary is $200,000 to $250,000 annually, plus equity. Visa sponsorship is not available. LOCATION On-site in San Francisco, California, United States, five days per week.