Founding Engineer

Headcount: 1

Job Details

• Experience: 0–3 years
• Salary: Not specified
• Equity: Competitive equity
• Visa sponsorship: Not available
• Employment type: Full-time
• Work arrangement: In person, five days a week, at our San Francisco office

Benefits & Perks

• Free lunch and dinner ($35 stipend on Uber Eats or DoorDash)
• Office gym
• Direct working relationship with the founding team
• High-impact founding role at an ad network for AI

About This Role

We are hiring a Founding Engineer to own the brain of our ad network: the engine that decides, in real time, which ad reaches which user and when across millions of daily interactions. This is a founding role spanning data pipelines, models, and production serving, with direct business impact at every layer. You’ll report to the Co-Founder and work closely with the founders and the small engineering team. This role is in person at our San Francisco office, five days a week.

We are looking for a true generalist with genuine technical depth: someone comfortable with infrastructure serving millions of users, classical ML models, and AI agents, who reasons about systems from first principles rather than simply assembling off-the-shelf AI tooling. You’ll inherit a working recommendation stack with real traffic and open problems, including delayed rewards, fatigue modeling, and cold start, and help define the approach. AdTech experience is a plus, not a requirement; being a gamer matters more. Applicants must be U.S. citizens or green card holders. Visa sponsorship is not available.

What You’ll Own

• Recommendation engine: Design and ship a low-latency ad-ranking system (retrieval, ranking, and reranking) that selects the optimal campaign and creative, including playable game ads, for each ad opportunity while balancing advertiser ROAS with user experience.
• ML training infrastructure: Architect the data pipelines and feature stores that power continuous model training across reward signals on different timelines: clicks (seconds), installs (hours), and conversions (days).
• User and context modeling: Build representations of user behavior from conversational data, engagement history, and contextual signals (geography, device, session context, and characters interacted with) to power personalization.
• Serving infrastructure: Build the stack for sub-second latency and cost efficiency under tight per-impression unit economics.
• Generative ad agents: Build agents that generate and ship playable and video ad variants on the fly, feeding performance data back into the recommendation engine.

What’s Already Live

The hire will inherit a working system with real traffic, not a blank slate.

• The recommendation stack this role owns is already serving ads across millions of daily interactions, reaching 30M+ users and supporting millions of dollars in annualized ad spend.
• Dozens of AI-generated playable mini-game and video ads are running in production inside major AI apps, built on our own playable engine and editor.
• Our own ad SDK (Swift, Kotlin, React, and React Native) is live in top App Store and Google Play apps.

The Team

Join a small San Francisco team with three exits and experience from Google, Blackstone, Bain Capital, PayPal, and DraftKings. The company is backed by a16z. The Founding Engineer will have ownership, equity, and a direct line to what ships.

Requirements

• Have shipped an ML or AI system in production.
• Have experience with backend systems, data pipelines, and serving infrastructure.
• Be an active builder, with a GitHub profile or side projects.
• Show high agency and an ability to ship quickly.
• Explain clearly and concisely what you built and why.