Senior Machine Learning Engineer - Ranking

QuinStreet powers digital media performance marketplaces using AI-driven matching technologies to connect consumers with brands. The Senior Machine Learning Engineer will advance ranking, prioritization, and personalization algorithms by designing experiments, building reliable signals and feature pipelines, managing model uncertainty and drift, and partnering cross-functionally to deliver production solutions.

Responsibilities:

• Design and improve ranking systems through rigorous measurement and experimentation; translate broad goals into clear metrics and deliver steady, validated gains
• Advance evaluation practices (clean test design, offline & online alignment) and help teams make evidence-based decisions
• Build high-value signals and features with reliable offline/online pipelines and robust monitoring. Incorporate content understanding signals such as text/image/metadata
• Make uncertainty-aware decisions; handle drift and calibration so models remain stable and trustworthy over time
• Partner with Engineering, Product, Business and Analytics to ship resilient solutions end-to-end

Requirements:

• Advanced degree (MS/PhD) in CS, Statistics, or related field, with 3+ years post-PhD or 5+ years industry experience
• Strong foundations in applied ML, statistics, and optimization with demonstrated impact in ranking/recommendations
• Proficiency in Python and solid software engineering practices (testing, CI/CD)
• Experience working with large-scale datasets, distributed systems, and latency-sensitive production ML
• Clear communication, cross-functional collaboration, and an ownership mindset
• Demonstrated success in delivering production-grade ranking systems with measurable business impact
• Track record building feature/signals pipelines, feature stores, and observability for ML systems
• Depth in experimentation and metrics design, including large-scale A/B testing and variance reduction
• Familiarity with monitoring, calibration, concept drift detection, and adaptive or online learning
• Proficiency in SQL is desired
• Knowledge about Linear Algebra, Combinatorial optimization is desired
• Proficiency in scalable software design and development
• Exposure to multimodal signals (text/image/metadata) is a plus, not required