Senior Principal Software Engineer, Ads Quality

Snap Inc is a technology company. We believe the camera presents the greatest opportunity to improve the way people live and communicate. Snap contributes to human progress by empowering people to express themselves, live in the moment, learn about the world, and have fun together. The Company operates Snapchat , a visual messaging app that enhances your relationships with friends, family, and the world, and Specs Inc. , a wholly-owned subsidiary dedicated to making computing more human, in addition to Bitmoji , Saturn, and other digital services. Snap Engineering teams build fun and technically sophisticated products that reach hundreds of millions of Snapchatters around the world, every day. We’re deeply committed to the well-being of everyone in our global community, which is why our values are at the root of everything we do. We move fast, with precision, and always execute with privacy at the forefront. We’re looking for a Senior Principal Software Engineer to lead the technical direction of Ads Quality within Snap’s Ads Platform team, with a focus on Ads Marketplace. Our marketplace connects advertiser demand with opportunities across Snapchat, deciding how budgets are spent, which ads are shown, and when and where they appear. As a senior individual contributor, you will shape the multi-year strategy and architecture for bidding, pacing, auctions, inventory and traffic optimization, and ad reranking. You will work across engineering, product, data science, and ML teams to improve advertiser performance and grow sustainable revenue while delivering a relevant, engaging experience for Snapchatters. What you’ll do: Set the multi-year technical strategy and architecture for Ads Marketplace, connecting investments across bidding, pacing, auctions, inventory, traffic optimization, and ad reranking. Design and scale bidding, budget allocation, and pacing algorithms that help advertisers achieve their goals with efficient spend and predictable delivery under changing marketplace conditions. Advance auction mechanisms, pricing, and allocation algorithms to improve advertiser value and marketplace efficiency, accounting for interactions with ranking, bidding, and pacing. Lead inventory and traffic optimization across Snapchat surfaces, improving ad load, placement, and demand allocation while balancing monetization with long-term user engagement. Develop ad reranking and slate optimization approaches that account for relevance, diversity, repetition, and the surrounding user experience, in partnership with Ads Ranking and consumer product teams. Establish objectives, evaluation methods, and experimentation standards that measure incremental marketplace impact, account for feedback loops and interference, and protect advertiser and user outcomes. Lead complex initiatives across teams, resolve architectural trade-offs and dependencies, and stay hands-on through prototyping, critical implementation, and production problem solving. Raise the engineering bar for reliability, latency, scalability, and cost efficiency; mentor senior engineers and technical leaders, and build shared technical foundations that enable teams to deliver independently. Knowledge, Skills & Abilities: Deep expertise in one or more areas of ads marketplace optimization, with the ability to reason about interactions across bidding, pacing, auctions, ranking, and user experience. Strong foundations in algorithms, optimization, statistics, and distributed systems, with the judgment to choose practical approaches for real-time production environments. Excellent programming and software design skills, including debugging, performance analysis, testing, and operating highly available systems at scale. Ability to turn ambiguous business and technical problems into a coherent strategy, measurable objectives, and an executable roadmap across multiple teams. Strong technical judgment in balancing advertiser outcomes, revenue, user engagement, system complexity,