Data Scientist

Position Summary

Cortex Team is Walmart’s core A.I. conversational platform, powering the vision of delivering the world’s best personal assistants to Walmart’s customers, accessible via natural voice commands, text messages, rich UI interactions, and a mix of all of the above via multi‑modal experiences. We believe conversations are a natural and powerful user interface for interacting with technology and enable a richer customer experience both online and in-store.

We are building and designing the next generation of Natural Language Understanding (NLU) services that other teams can easily integrate and leverage, and build rich experiences: from pure voice and text shopping assistants (Siri, Sparky), to customer care channels, to mobile apps with rich, intertwined, multi‑modal interaction modes (Me@Walmart).

We need passionate and seasoned NLP data scientists to help us improve and evolve our capabilities, taking into account the full conversational context, multi‑modal interactions, and an ever increasing list of use cases. You will have the opportunity to influence the design, architecture, and implementation of an innovative, mission critical product, driven by data science, used every day by many customers.

Build and deploy end‑to‑end generative AI systems, design and implement NLU/NLP models, fine‑tune transformer models, analyze conversational data, improve model performance, develop production pipelines, and write white papers, blogs, demos, etc.

• Master’s degree or certification in Machine Learning, Computer Science, Engineering, Mathematics, Statistics or related field, with 3+ years work experience.
• Extensive experience with NLU/NLP, recent deep ML models (e.g., Transformers, BERT, Llama, GPTs, Gemini) and safe fine‑tuning of these.
• Extensive experience in designing, developing and deploying end‑to‑end generative AI systems using transformer‑based LLM architectures (both open source and close source).
• Experience with Python; solid knowledge of SQL.
• Hands‑on experience with classical ML models, test/train/evaluation metrics, key parameters/techniques that affect model performance.
• Understanding of relevant statistical measures such as confidence intervals, significance of error measurements, development and evaluation data sets.
• Ability to take a project from scoping requirements through launch.
• Continuous drive to explore, improve, automate, and optimize models and products.
• Experience analyzing conversational data to identify patterns and conducting error/deviation analysis; passion for fixing data issues.
• Excellent oral and written communication skills.

• PhD in a relevant field (Machine Learning, Computer Science, Engineering, Mathematics, Physics, Statistics or a related field).
• Experience developing multimodal solutions for generative AI and related applications at scale.
• Exposure to real‑world, production‑grade agentic systems.
• Familiarity with LLMs serving optimizations and multi‑LoRa.
• Ability to develop experimental and analytic plans for data modeling processes, use of strong baselines, accurately determine cause and effect.
• Strong attention to detail and exceptional organization.
• Proven ability to achieve results in a fast‑paced, highly collaborative environment.
• Hands‑on expertise across disparate technologies and the full model lifecycle, from data pipelines to model serving and ML‑ops.

Walmart offers competitive pay, performance‑based bonus awards and other benefits such as medical, vision, dental coverage, 401(k), stock purchase, company‑paid life insurance, paid time off, parental leave, family care leave, jury duty, voting, short‑term and long‑term disability, company discounts, military leave pay, adoption and surrogacy expense reimbursement, and more. Additional compensation may include stock. PTO and PPTO are available and may be used for vacation, sick leave, holidays, or other purposes.

680 W California Ave, Sunnyvale, CA 94086‑4834, United States of America