Principal, Machine Learning Engineer

Walmart•Sunnyvale, CA

13d•$169,000 - $338,000

About The Position

Walmart Scintilla is a commercial data and AI platform powering the suppliers of the world’s largest retailer. With access to one of the most diverse and scaled data ecosystems anywhere, we transform the data of a Fortune-1 company into insight, recommendation, and innovation that drives impact for customers, merchants, and suppliers. Our teams are pioneering the use of Generative AI, agentic intelligence, and advanced ML to reimagine customer experiences, optimize operations, and unlock new business models. For external candidates, it’s a chance to join a team that is shaping the future of retail AI and setting industry benchmarks. What you'll do : We are seeking a Principal Machine Learning Engineer – Applied AI & Data Science to define and solve the most ambiguous, high-value problems in retail using cutting-edge techniques. This role is a highly specialized Applied Science position, requiring a deep fusion of AI/ML scientific methodology, advanced GenAI modeling, and strategic business problem-solving. Building on our public vision of “Four Super Agents,” you will apply state-of-the-art AI and traditional DS techniques to define, validate, and measure impact across customer-facing experiences and enterprise operations. Our team is driving diverse, high-impact enterprise initiatives, including recommendation platforms, customer voice, market research, product innovation, customer attitudinal segmentation, deep research, agent based simulations, and many more. What You'll bring : These initiatives require advanced expertise in the following capabilities: 1. Core Data Science & Predictive AI ● Frame ambiguous business questions into testable hypotheses and measurable data science projects with clear success metrics. ● Design and execute rigorous experimentation (A/B testing, causal inference, synthetic control) to quantify the impact of AI initiatives and business interventions. ● Own the end-to-end data science lifecycle, from data discovery, rigorous data cleansing, and feature engineering to model building, validation, story-telling and insight communication. ● Drive deep analytical insights from petabytes of data, translating complex statistical findings into clear, actionable narratives for executive leadership and product teams. ● Champion data quality and ensure all analyses meet the highest standards of scientific validity, fairness, and responsible AI compliance. 2. Generative & Agentic AI Modeling ● Lead the scientific evaluation of all Generative AI outputs, ensuring models meet high standards for safety, accuracy, fairness, and responsible AI compliance, including continuous monitoring for bias and drift. ● Design and implement advanced RAG and multi-modal fusion techniques for deep research, leveraging external knowledge sources and proprietary data to create enhanced decision support systems. ● Apply and optimize emerging LLM techniques such as prompt engineering, LoRA/PEFT fine-tuning, and reinforcement learning from human feedback (RLHF/DPO) to tailor models for specific retail tasks. 3. Leadership & Influence ● Serve as a technical leader and mentor, guiding senior Data Scientists and analysts to build depth and expertise in modern data science methodologies. ● Influence cross-functional strategy, ensuring analytical approaches and model output align with Walmart’s broader product and engineering vision. ● Contribute to Walmart’s AI reputation through thought leadership—publishing, presenting, and showcasing innovations internally and externally. Above all, we're looking for a leader defined by curiosity and the resilience to thrive in complex, high-uncertainty environments. The ideal Principal has a deep technical science and engineering background—mastery of algorithmic thinking, statistical rigor, and strong coding skills. We value the efficient use of AI coding assistants but expect strong, independent coding prowess. Your willingness to work hard and quickly get up to speed on new domains is the most critical asset. If you have the foundational strength and the drive to lead our next-era AI journey in retail, we encourage you to apply.

Requirements

Scientific Rigor & Experimentation: Deep, applied expertise in Traditional AI/ML models, Advanced Statistical Modeling, Causal Inference, and Experimentation Design (e.g., A/B testing, uplift modeling, and synthetic control).
Strategic Problem Framing: Proven ability to translate the most ambiguous, high-value business challenges into precise, testable data science hypotheses and scalable analytical roadmaps.
Generative & Agentic AI Application: Practical expertise in leveraging and scientifically validating Generative AI techniques (LLMs, RAG, prompt optimization) for advanced data summarization, deep research, and rapid hypothesis generation.
Production and Impact Delivery: A demonstrable track record of owning and driving the end-to-end data science lifecycle—from concept and feature engineering to model validation, deployment, and quantified business results.
Technical Mastery: Strong, production-level coding skills in Python (or R), mastering data science libraries (e.g., pandas, scikit-learn) and deep learning frameworks (TensorFlow/PyTorch) for model development.
Technical Leadership: Established experience serving as a technical leader, mentoring other scientists, and influencing cross-functional product and engineering decisions through clear analytical alignment.
Option 1: Bachelor's degree in computer science, computer engineering, computer information systems, software engineering, or related area and 5 years’ experience in software engineering, machine learning engineering, AI systems or related area.
Option 2: 7 years’ experience in software engineering, machine learning engineering, AI systems or related area.
2 years’ supervisory experience.

Nice To Haves

Experience in market research, survey and voice of customer platforms.
Familiarity with probabilistic and Bayesian methods.
Exposure to multimodal systems (vision, speech, time series).
Strong presence in the Data Science community (publications, open-source contributions, conference talks).
Master’s degree in computer science, computer engineering, computer information systems, software engineering, or related area and 3 years' experience in software engineering, machine learning engineering, AI systems or related area.
We value candidates with a background in creating inclusive digital experiences, demonstrating knowledge in implementing Web Content Accessibility Guidelines (WCAG) 2.2 AA standards, assistive technologies, and integrating digital accessibility seamlessly.
The ideal candidate would have knowledge of accessibility best practices and join us as we continue to create accessible products and services following Walmart’s accessibility standards and guidelines for supporting an inclusive culture.

Responsibilities

Frame ambiguous business questions into testable hypotheses and measurable data science projects with clear success metrics.
Design and execute rigorous experimentation (A/B testing, causal inference, synthetic control) to quantify the impact of AI initiatives and business interventions.
Own the end-to-end data science lifecycle, from data discovery, rigorous data cleansing, and feature engineering to model building, validation, story-telling and insight communication.
Drive deep analytical insights from petabytes of data, translating complex statistical findings into clear, actionable narratives for executive leadership and product teams.
Champion data quality and ensure all analyses meet the highest standards of scientific validity, fairness, and responsible AI compliance.
Lead the scientific evaluation of all Generative AI outputs, ensuring models meet high standards for safety, accuracy, fairness, and responsible AI compliance, including continuous monitoring for bias and drift.
Design and implement advanced RAG and multi-modal fusion techniques for deep research, leveraging external knowledge sources and proprietary data to create enhanced decision support systems.
Apply and optimize emerging LLM techniques such as prompt engineering, LoRA/PEFT fine-tuning, and reinforcement learning from human feedback (RLHF/DPO) to tailor models for specific retail tasks.
Serve as a technical leader and mentor, guiding senior Data Scientists and analysts to build depth and expertise in modern data science methodologies.
Influence cross-functional strategy, ensuring analytical approaches and model output align with Walmart’s broader product and engineering vision.
Contribute to Walmart’s AI reputation through thought leadership—publishing, presenting, and showcasing innovations internally and externally.

Benefits

At Walmart, we offer competitive pay as well as performance-based bonus awards and other great benefits for a happier mind, body, and wallet.
Health benefits include medical, vision and dental coverage.
Financial benefits include 401(k), stock purchase and company-paid life insurance.
Paid time off benefits include PTO (including sick leave), parental leave, family care leave, bereavement, jury duty, and voting.
Other benefits include short-term and long-term disability, company discounts, Military Leave Pay, adoption and surrogacy expense reimbursement, and more.
You will also receive PTO and/or PPTO that can be used for vacation, sick leave, holidays, or other purposes.
The amount you receive depends on your job classification and length of employment.
It will meet or exceed the requirements of paid sick leave laws, where applicable.
For information about PTO, see https://one.walmart.com/notices .Live Better U is a Walmart-paid education benefit program for full-time and part-time associates in Walmart and Sam's Club facilities.
Programs range from high school completion to bachelor's degrees, including English Language Learning and short-form certificates.
Tuition, books, and fees are completely paid for by Walmart.
Eligibility requirements apply to some benefits and may depend on your job classification and length of employment.
Benefits are subject to change and may be subject to a specific plan or program terms.
For information about benefits and eligibility, see One.Walmart .
The annual salary range for this position is $169,000.00 - $338,000.00 Additional compensation includes annual or quarterly performance bonuses.
Additional compensation for certain positions may also include : - Stock