Senior Principal ML Engineer - Optimization

Salary: $260,000 - 330,000 per year Requirements:

• We need 10+ years of experience building production machine learning, ranking, recommendation, prediction, optimization, ads, marketplace, bidding, or pricing systems.
• We are looking for a strong grasp of supervised learning, ranking, calibration, causal reasoning, experimentation, statistical analysis, and model monitoring.
• We need experience building large-scale prediction or optimization systems in production.
• We value experience with CTR/CVR prediction, conversion modeling, bid optimization, value modeling, forecasting, calibration, or performance optimization.
• We expect the ability to assess model quality, business impact, system constraints, production tradeoffs, and online performance.
• We require experience working with large-scale data and distributed ML workflows.
• We need strong engineering skills in Python, Java, SQL, Spark, TensorFlow, PyTorch, XGBoost, or similar technologies.
• We look for the ability to lead technically through ambiguous, high-impact optimization challenges.
• We require a BS, MS, or PhD in Computer Science, Machine Learning, Statistics, Mathematics, Engineering, or a related technical field.

• We will build and enhance machine learning models for campaign optimization, prediction, ranking, bidding, forecasting, and calibration.
• We will design algorithms that improve advertiser outcomes while balancing spend delivery, cost efficiency, campaign goals, marketplace dynamics, and system constraints.
• We will work on large-scale ML systems using signals from auctions, impressions, clicks, video events, conversions, users, context, inventory, campaigns, and marketplace feedback.
• We will develop CTR, CVR, VCR, CPA, ROAS, app-install, user-value, and campaign-performance models.
• We will create bidding, pacing-aware optimization, ranking, exploration, and value-estimation approaches for performance advertising.
• We will improve model calibration, online and offline evaluation, experimentation, observability, and production feedback loops.
• We will reason through sparse conversions, delayed feedback, biased logs, cold-start campaigns, attribution noise, and online/offline metric mismatch.
• We will partner with signal engineering teams to define model-ready features, labels, attribution windows, negative examples, training data, and online serving needs.
• We will collaborate with engineering, product, analytics, and platform teams to turn model outputs into real-time decisioning systems.
• We will help evolve Activate from a media buying execution platform into a performance optimization platform.
• We will provide technical leadership and mentorship to engineers and applied scientists working on performance optimization problems.

• AI
• Support
• Java
• Machine Learning
• Mobile
• PyTorch
• Python
• SQL
• Spark
• TensorFlow
• Windows

More:

We are PubMatic, an AI-powered ad tech company delivering measurable advertising performance through an intelligent, unified platform that connects buyers, publishers, data partners, and commerce media across CTV, mobile app, and omnichannel environments. Our Activate platform is focused on the next generation of performance optimization, and we are hiring for a Senior Principal Machine Learning Engineer in Redwood City, California, with hybrid work arrangements and remote flexibility for the right candidate. We operate on a hybrid schedule of three days in the office and two days remote to support collaboration, innovation, and productivity. We offer a competitive benefits package that includes paid leave, paid holidays, healthcare, dental and vision coverage, disability and life insurance, commuter benefits, wellness programs, unlimited DTO in the U.S., mobile reimbursement, stocked pantries, and catered lunches five days a week. We are proud to be an equal opportunity employer and to foster a diverse and inclusive workplace. Compensation for this role is estimated at $260,000 to $330,000 USD in total compensation, with bonus, restricted stock units, and benefits included.

last updated 33 week of 2026